Pulmonary artery pressure in lymphangioleiomyomatosis: an echocardiographic study.

BACKGROUND: Exercise-induced hypoxemia is frequent in patients with lymphangioleiomyomatosis (LAM) and could be associated with pulmonary hypertension. The aims of this study were to determine the prevalence of pulmonary hypertension in patients with LAM, to identify physiologic parameters associated with its occurrence, and to evaluate the effect of oxygen on response to exercise. METHODS: Studies were performed in 120 patients. Complete data, including exercise echocardiography, pulmonary function testing, and standard cardiopulmonary exercise testing, were obtained in 95 patients. RESULTS: Resting pulmonary artery pressure (PAP) was 26+/-0.7 mm Hg (mean+/-SEM). Eight patients had pulmonary hypertension (43+/-3 mm Hg), and two patients had right ventricular dilatation. Ninety-five patients exercised (room air, n=64; oxygen, n=31) to a power of 58+/-2 W (49% of predicted) and an estimated peak oxygen uptake of 938+/-30 mL/min (56% of predicted). Sixty-one patients had a decline in arterial oxygen saturation (SaO2)>3%, and 56 patients had an elevation in PAP>40 mm Hg. Peak exercise PAP was negatively correlated with exercise Sao2 (p=0.0005). Multivariate analysis showed that exercise SaO2 was the best predictor of exercise PAP (p=0.012). CONCLUSIONS: Although resting pulmonary hypertension is rare in patients with LAM, a rise in PAP at low exercise levels occurs frequently, in part related to exercise-induced hypoxemia. Optimization of oxygen administration during activities of daily living should be undertaken in patients with LAM to prevent hypoxemia and exercise-induced pulmonary hypertension.

Left ventricular systolic function during stress echocardiography exercise in subjects with asymptomatic hereditary hemochromatosis.

There is no information available on left ventricular (LV) systolic function and the response to stress echocardiography in asymptomatic subjects with hereditary hemochromatosis (HH). To evaluate this topic, 43 asymptomatic subjects with HH homozygous for the C282Y HFE gene mutation (22 untreated subjects [group A] and 21 long-term treated subjects [group B]) were compared with 21 age- and gender-matched normal volunteers negative for HFE mutations. Contractile reserve, as a measure of LV systolic function, was assessed using continuous echocardiographic imaging and electrocardiography during supine bicycle exercise. Nineteen subjects in group A had repeat tests after 6 months of induction phlebotomy therapy to assess the effect of iron removal. Exercise performance and hemodynamic variables of supine bicycle exercise were comparable between subjects with HH and controls. LV contractile reserve of asymptomatic subjects with HH was not impaired at either a 75-W submaximal exercise level (mean +/- SD difference in ejection fraction from baseline 13.8 +/- 6.2%, 11.5 +/- 6.8%, and 13.4 +/- 7.8% in groups A, B, and C, respectively; p = NS for all by analysis of variance) or at peak exercise (difference in ejection fraction from baseline 18.9 +/- 6.9%, 18.4 +/- 7.8%, and 20.3 +/- 8.1% in groups A, B, and C, respectively; p = NS for all by analysis of variance). However, the incidence of abnormal ischemic stress electrocardiographic responses was more frequent in subjects with HH as a whole (33%) compared with normal subjects (10%). Stress imaging revealed no regional wall motion abnormalities, suggesting that these were false-positive results. Iron removal by induction phlebotomy did not affect stress echocardiographic performance. In conclusion, LV systolic function during exercise in asymptomatic subjects with HH is preserved, and 6-month induction phlebotomy does not affect stress echocardiographic performance.

Left atrial volumetric remodeling is predictive of functional capacity in nonobstructive hypertrophic cardiomyopathy.

BACKGROUND: The left atrium is afterload sensitive, responding to immediate changes in left ventricular (LV) diastolic pressure, and left atrial volumetric remodeling has been reported in conditions associated with abnormal diastolic function. We examined the relationship between left atrial volumetric remodeling and objective measures of exercise capacity in patients with nonobstructive hypertrophic cardiomyopathy (HCM). METHODS: We compared LA volume indices, other 2-dimensional and Doppler echocardiographic parameters, invasive hemodynamic measures, and magnetic resonance imaging (MRI)-derived LV mass with exercise duration, maximal oxygen uptake (MV* O2), anaerobic threshold (AT), and ventilatory efficiency (VE/V* CO2 slope) in 43 patients with nonobstructive HCM. Patients underwent cardiac catheterization within 48 hours and metabolic stress testing within 1 week of their echocardiogram and MRI examinations. RESULTS: Left atrial volume at end-ventricular systole (LA max) and end-atrial emptying (LA min) correlated with MV* O2 (r = -0.39, P < .01 for both), AT (r = -0.42, r = -0.39, respectively, P < .01 for both), and VE/V* CO2 slope (r = 0.45, P = .003; r = 0.41, P = .008). Patients with an LA max > or =33 mL/m2 had significantly lower MV* O2 (P = .025) and AT levels (P = .017) and higher VE/V* CO2 slope levels (P = .004) as compared with patients with a smaller LA size. In multivariate analysis, MRI-determined LV mass, which was not a univariate correlate of exercise tolerance, provided additional effect when combined with LA volume index. CONCLUSIONS: Left atrial volumetric remodeling predicts exercise capacity in nonobstructive HCM and may reflect chronic LV diastolic burden. This simple noninvasive measure of LA size may provide a long-term indication of the effects of chronically elevated filling pressures in patients with HCM and further studies testing its prognostic value are necessary.