Jin-Mi Kim

Clinical outcomes of exercise-induced pulmonary hypertension in subjects with preserved left ventricular ejection fraction: implication of an increase in left ventricular filling pressure during exercise

Objective To investigate clinical outcomes of exercise-induced pulmonary hypertension (PH) and implications of an increase in left ventricular (LV) filling pressure during exercise in subjects with preserved LV ejection fraction. Design Longitudinal follow-up study. Setting Subjects who were referred for diastolic stress echocardiography. Patients and methods The ratio of transmitral and annular velocities (E/Ea) and pulmonary artery systolic pressure (PASP) at rest and during exercise were measured in 498 subjects (57±11 years; 201 male). Exercise-induced PH was defined as present if PASP ≥50 mm Hg at 50 W of exercise, and an increase in LV filling pressure during exercise was present if E/Ea ≥15 at 50 W. Main outcome measures A combination of major cardiovascular events and any cause of death. Results During a median follow-up of 41 months, there were 14 hospitalisations and four deaths. Subjects with exercise-induced PH had significantly worse clinical outcomes than those without (p=0.014). Subjects with exercise-induced PH associated with an increase in E/Ea during exercise had significantly worse outcomes than other groups (p<0.001). However, prognosis was similar between subjects with exercise-induced PH without an increase in E/Ea and those without exercise-induced PH. In subjects with exercise-induced PH, E/Ea at 50 W was an independent predictor of adverse outcomes (HR 1.37; 95% CI 1.02 to 1.83; p=0.036). Conclusions Exercise-induced PH provides prognostic information in subjects with preserved LV ejection fraction. The excess risk of exercise-induced PH is restricted to subjects with an increase in estimated LV filling pressure during exercise.

Left Ventricular Diastolic Functional Reserve during Exercise in Patients with Impaired Myocardial Relaxation at Rest

Background: Patients with similar grade diastolic dysfunction at rest may have a spectrum of alterations in diastolic function during exercise. Objective: To evaluate (a) whether exercise could unmask further diastolic abnormalities not evident during rest; (b) whether diastolic functional reserve during exercise is associated with exercise capacity. Methods: 141 subjects (77 male, mean (SD) age 62 (9)) with abnormal left ventricular (LV) relaxation (mitral E/A <0.75) and/or deceleration time >240 ms, underwent graded supine bicycle exercise with simultaneous respiratory gas analysis and two-dimensional and Doppler echocardiographic study. Mitral inflow and annular velocities were measured at rest and during exercise. The LV diastolic function reserve index (DFRI) was calculated. Results: Patients were classified into two groups: group 1 (n = 64), DFRI <13.5; group 2 (n = 77), DFRI ⩾13.5. The ratio of E/E′ to stroke volume was used as an index of ventricular elastance (Ed). No significant differences between the groups in mitral inflow and annular velocities at rest were found. Mean (SD) Ed was not significantly different at rest between the groups (0.19 (0.07) vs 0.18 (0.06), p = 0.29). Ed was significantly higher during exercise in group 1 than in group 2 (25 W, 0.21 (0.09) vs 0.14 (0.04), p<0.001; 50 W, 0.22 (0.10) vs 0.15 (0.04), p<0.001). Group 1 subjects had a shorter exercise duration (8.2 (2.7) vs 9.4 (3.7) min, p = 0.04) and lower peak oxygen consumption (17.5 (4.5) vs 20.2 (5.4) ml/kg/min, p = 0.005). Conclusions: Despite similar mitral flow and annular velocities at rest, different responses to exercise were seen in patients with abnormal LV relaxation at rest. Lower LV diastolic functional reserve was associated with higher ventricular elastance during exercise, and reduced exercise capacity.

Gender-Related Difference in Arterial Elastance During Exercise in Patients With Hypertension

Exercise intolerance and heart failure with preserved ejection fraction are common in females. Recently, arterial stiffness has been suggested to be a significant contributor in the development of heart failure. How gender difference affects arterial stiffening and its response to exercise is not well known. We hypothesized that arterial elastance index during exercise would be more abnormal in females with hypertension than males. Arterial elastance index was estimated as arterial end systolic pressure/stroke volume controlled for body surface area and was measured at rest and during graded supine bicycle exercise (25 watts, 3-minute increments) in 298 patients with hypertension (149 males; 149 females; mean age, 59). The subjects were divided into 2 groups by gender. Exercise duration was significantly shorter in females compared to males (692±222 versus 483±128 seconds, P<0.001). Although arterial elastance index at baseline was significantly higher in males, the magnitude of increase was steeper in females with the magnitude of change at 75 W of exercise being significantly higher in females compared to males (0.69±0.83 versus 0.43±0.69, P=0.018). Arterial elastance index at each stage of exercise up to 75 W was independently associated with decreased exercise duration. In conclusion, despite lower arterial elastance index at rest, the increase during exercise was steeper in women with hypertension, suggesting a gender-related difference in dynamic arterial stiffness. The arterial elastance index during exercise was significantly associated with exercise duration in patients with hypertension.

Impact of left ventricular longitudinal diastolic functional reserve on clinical outcome in patients with type 2 diabetes mellitus

Background Left ventricular longitudinal diastolic functional reserve (DFR), as assessed by the change in early diastolic mitral annular velocity (E′) during exercise, is abnormal in patients with type 2 diabetes mellitus (DM). However, the impact of left ventricular longitudinal DFR on clinical outcome has not been explored. This study evaluated the incremental prognostic value of left ventricular DFR in patients with type 2 DM without overt heart disease. Methods Of 1485 patients who were referred for exercise stress echocardiography, 197 consecutive patients (mean age, 58 years; 84 men) with type 2 DM without overt heart disease were identified. Left ventricular longitudinal DFR was defined as the change in E′ from resting to exercise (ΔE′). The endpoint was a composite of death and hospitalisation for heart failure (HF). Results During a median follow-up of 57 months (range 6–90), 18 of 197 patients (9.1%) had adverse events (12 deaths, six hospitalisations for HF). Independent predictors of adverse events in a Cox regression analysis were estimated glomerular filtration rate (HR 0.97; 95% CI 0.95 to 0.98; p<0.001), DM duration (HR 1.07; 95% CI 1.01 to 1.14; p=0.018) and ΔE′ (HR 0.58; 95% CI 0.40 to 0.85; p=0.005). In an incremental model, the addition of stress echo data significantly increased the χ2 of the clinical and resting left ventricular function model, from 40.5 to 46.6 (p=0.005). Conclusion Assessment of left ventricular longitudinal DFR during exercise provided incremental prognostic information in patients with type 2 DM without overt heart disease.