Mitral systolic velocity at peak exercise predicts impaired exercise capacity in patients with heart failure with preserved ejection fraction

Left Atrial Stiffness Index as a Predictor of Effort Intolerance and Hemodynamics Evaluated by Invasive Exercise Stress Testing in Degenerative Mitral Regurgitation

In patients with degenerative mitral regurgitation (DMR), peak oxygen consumption is the significant prognostic factor, and exercise intolerance has been considered a trigger for surgical intervention. The significant mitral regurgitation (MR) induces left atrial (LA) remodeling, but the significance of LA stiffness calculated by the ratio of E/e' to LA reservoir strain in degenerative MR has not been elucidated. A total of 30 patients with asymptomatic or minimally symptomatic grade ≥III + DMR underwent the cardiopulmonary exercising test simultaneously with invasive hemodynamic assessment. LA stiffness index significantly correlated with exercise hemodynamic deterioration, including pulmonary arterial wedge pressure (r = 0.71, p <0.01), systolic pulmonary arterial pressure at peak exercise (r = 0.73, p <0.01), and pulmonary circulatory reserve (mean pulmonary arterial pressure/cardiac output slope, r = 0.45, p = 0.012). Multiple linear regression analysis revealed that the higher LA stiffness index was significantly associated with decreased percent predicted peak oxygen consumption (per 0.1 increase, β -4.0, 95% confidence interval -6.9 to -1.3, p <0.01) independently of MR deterioration during exercise. In conclusion, increased LA stiffness was associated with exercise intolerance through hemodynamic deterioration during exercise in patients with asymptomatic or minimally symptomatic severe DMR.

Exercise Systolic Reserve and Exercise Pulmonary Hypertension Improve Diagnosis of Heart Failure With Preserved Ejection Fraction

Aims

Diastolic stress testing (DST) is recommended to confirm heart failure with preserved ejection fraction (HFpEF) in patients with exertional dyspnea, but current algorithms do not detect all patients. We aimed to identify additional echocardiographic markers of elevated pulmonary arterial wedge pressure during exercise (exPAWP) in patients referred for DST.

Methods and Results

We identified candidate parameters in 22 patients referred for exercise right heart catheterization with simultaneous echocardiography. Elevated exPAWP (≥25 mmHg) was present in 14 patients, and was best identified by peak septal systolic annular velocity <9.5 cm/s [exS', area under the receiver operating characteristic curve (AUC) 0.97, 95% confidence interval 0.92–1.0] and mean pulmonary artery pressure/cardiac output slope ≥3.2 mmHg/L [mPAP/CO, AUC 0.88 (0.72–1.0)]. We propose a decision tree to identify patients with elevated exPAWP. Applying this decision tree to 326 patients in an independent non-invasive DST cohort showed that patients labeled as “high probability of HFpEF” (n = 85) had reduced peak oxygen uptake [13.0 (10.7–15.1) mL/kg/min, p < 0.001 vs. intermediate/low probability], high H2FPEF score [53 (40–72) %, p < 0.001 vs. intermediate/low probability], and typical clinical characteristics. The diagnostic yield of DST increased from 11% using exercise E/e', to 62% using the decision tree.

Conclusion

In DST for suspected HFpEF, exS' was the most accurate echocardiographic parameter to identify elevated PAWP. We propose a decision tree including exS' and mPAP/CO for interpretation of DST. Application of this decision tree revealed typical HFpEF characteristics in patients labeled as high probability of HFpEF, and substantially reduced the number of inconclusive results.

Left ventricular concentric remodeling and impaired cardiorespiratory fitness in patients with heart failure and preserved ejection fraction

BACKGROUND

Left ventricular (LV) concentric remodeling refers to a process by which increased LV relative wall thickness alters myocardial geometry, resulting in reduced LV end-diastolic volume (LVEDV) and stroke volume (SV). While the degree of concentric remodeling is a negative prognostic factor in heart failure with preserved ejection fraction (HFpEF), it is not known how it contributes to cardiorespiratory fitness (CRF).

METHODS

We performed a retrospective analysis of patients with HFpEF who underwent treadmill single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) and cardiopulmonary exercise testing (CPX). From exercise SPECT-MPI, we recorded postexercise LVEDVi, LVESVi, SVi, LVEF, the presence and extent of perfusion defects, and perfusion reversibility. Peak oxygen consumption (VO<inf>2</inf>), the oxygen uptake efficiency slope (OUES), oxygen (O<inf>2</inf>) pulse, ventilatory efficiency (V<inf>E</inf>/VCO<inf>2</inf> slope), ventilatory anaerobic threshold, respiratory exchange ratio, exercise time, and maximum heart rate were obtained from CPX. Data are expressed as mean (±standard deviation). Univariate and multivariate linear regression was performed.

RESULTS

We identified 23 subjects who had completed both an exercise SPECT-MPI and a CPX. Patients were more commonly women (83%), black (65%), middle age (50 [±7.3] years), and obese (Body Mass Index [BMI] 39.7 [±6.0] kg/m²). Greater LVEDVi and LVESVi correlated positively with peak VO<inf>2</inf> (R=+0.648, P=0.001; R=+0.601, P=0.002), O<inf>2</inf> pulse (R=+0.686, P<0.001; R=+0.625, P=0.001) and OUES (R=+0.882, P<0.001; R=+0.779, P<0.001). The LVEF correlated inversely with peak VO<inf>2</inf> and OUES (R=-0.450, P=0.031; R=-0.485, P=0.035). Perfusion defect area, grade of severity, and presence of reversibility were not associated with CRF variables.

CONCLUSIONS

Postexercise reduced LV volumes correlate with measures of impaired CRF in patients with HFpEF, thus supporting a pathophysiologic role of concentric remodeling in impaired CRF in HFpEF.