Pulmonary hypertension detection by computed tomography pulmonary transit time in heart failure with reduced ejection fraction.

AIMS: To evaluate the relationships between pulmonary transit time (PTT), cardiac function, and pulmonary haemodynamics in patients with heart failure with reduced ejection fraction (HFrEF) and to explore how PTT performs in detecting pulmonary hypertension (PH). METHODS AND RESULTS: In this prospective study, 57 patients with advanced HFrEF [49 men, 51 years ± 8, mean left ventricular (LV) ejection fraction 26% ± 8] underwent echocardiography, right heart catheterization, and cardiac computed tomography (CT). PTT was measured as the time interval between peaks of attenuation in right ventricle (RV) and LV and was compared between patients with or without PH and 15 controls. PTT was significantly longer in HFrEF patients with PH (21 s) than in those without PH (11 s) and controls (8 s) (P < 0.001) but not between patients without PH and controls (P = 0.109). PTT was positively correlated with pulmonary artery wedge pressure (PAWP) (r = 0.74), mean pulmonary artery pressure (r = 0.68), N-terminal pro-B-type natriuretic peptide (r = 0.60), mitral (r = 0.54), and tricuspid (r = 0.37) regurgitation grades, as well as with LV, RV, and left atrial volumes (r from 0.39 to 0.64) (P < 0.01). PTT was negatively correlated with cardiac index (r = -0.63) as well as with LV (r = -0.66) and RV (r = -0.74) ejection fractions. PAWP, cardiac index, mitral regurgitation grade, and RV end-diastolic volume were all independent predictors of PTT. PTT value ≥14 s best-detected PH with 91% sensitivity and 88% specificity (area under the receiver operating characteristic curve: 0.95). CONCLUSION: In patients with HFrEF, PTT correlates with cardiac function and pulmonary haemodynamics, is determined by four independent parameters, and performs well in detecting PH.

Pulmonary hypertension due to left heart disease: diagnostic and prognostic value of CT in chronic systolic heart failure.

OBJECTIVES: To evaluate the ability of chest computed tomography (CT) to predict pulmonary hypertension (PH) and outcome in chronic heart failure with reduced ejection fraction (HFrEF). METHODS: We reviewed 119 consecutive patients with HFrEF by CT, transthoracic echocardiography (TTE) and right heart catheterization (RHC). CT-derived pulmonary artery (PA) diameter and PA to ascending aorta diameter ratio (PA:A ratio), left atrial, right atrial, right ventricular (RV) and left ventricular volumes were correlated with RHC mean pulmonary arterial pressure (mPAP) . Diagnostic accuracy to predict PH and ability to predict primary composite endpoint of all-cause mortality and HF events were evaluated. RESULTS: RV volume was significantly higher in 81 patients with PH compared to 38 patients without PH (133 ml/m2 vs. 79 ml/m2, p < 0.001) and was moderately correlated with mPAP (r=0.55, p < 0.001). Also, RV volume had higher ability to predict PH (area under the curve: 0.88) than PA diameter (0.79), PA:A ratio (0.76) by CT and tricuspid regurgitation gradient (0.83) and RV basal diameter by TTE (0.84, all p < 0.001). During the follow-up period (median: 3.4 years), 51 patients (43%) had HF events or died. After correction for important clinical, TTE and RHC parameters, RV volume (adjusted hazard ratio [HR]: 1.71, 95% CI 1.31-2.23, p < 0.001) and PA diameter (HR: 1.61, 95% CI 1.18-2.22, p = 0.003) were independent predictors of the primary endpoint. CONCLUSION: In patients with HFrEF, measurement of RV volume and PA diameter on ungated CT are non-invasive markers of PH and may help to predict the patient outcome. KEY POINTS: • Right ventricular (RV) volume measured by chest CT has good ability to identify pulmonary hypertension (PH) in patients with chronic heart failure (HF) and reduced ejection fraction (HFrEF). • The accuracy of pulmonary artery (PA) diameter and PA to ascending aorta diameter ratio (PA:A ratio) to predict PH was similar to previous studies, however, with lower cut-offs (28.1 mm and 0.92, respectively). • Chest CT-derived PA diameter and RV volume independently predict all-cause mortality and HF events and improve outcome prediction in patients with advanced HFrEF.

Usefulness of tissue Doppler imaging to evaluate pulmonary capillary wedge pressure during exercise in patients with reduced left ventricular ejection fraction.

The early diastolic transmitral velocity/tissue Doppler imaging mitral annular early diastolic velocity (E/e') ratio is used to estimate left ventricular (LV) filling pressures at rest. However, there are only limited data that validate its use during exercise. Accordingly, the aim of this study was to test the ability of E/e' to estimate pulmonary capillary wedge pressure (PCWP) during symptom-limited exercise in patients with LV systolic dysfunction. Forty patients with severe LV dysfunction and heart failure symptoms (54 ± 12 years, 28 men) underwent simultaneous Doppler assessment of E/e' and right-sided cardiac catheterization at rest and during a symptom-limited exercise test, at steady state levels of 30%, 60%, and 90% of their maximal exercise capacity. During exercise, all 40 patients successfully completed stage 1, yielding 40 pairs of data for comparison. Eighteen patients also successfully completed stage 2, and 5 patients also made it through stage 3, yielding 23 additional data pairs. In total, there were thus 63 pairs of data available during exercise. With exercise, heart rate increased from 77 ± 14 to 112 ± 21 beats/min. Septal E/e' at rest correlated well with PCWP at rest (r = 0.75, p <0.01). PCWP at rest also correlated with resting mitral deceleration time (r = 0.32, p <0.01) and with the transmitral E/A ratio (r = 0.74, p <0.01). During exercise, the correlation between septal E/e' and PCWP was weaker (r = 0.57, p <0.01) and was shifted to the right. This rightward shift was observed in patients with both separated or merged E and A velocities. In conclusion, in patients with severe LV dysfunction, although E/e' allows accurate estimation of PCWP at rest, it appears less reliable for estimating LV filing pressure during exercise.

Is postsystolic shortening a marker of viability in chronic left ventricular ischemic dysfunction? Comparison with late enhancement contrast magnetic resonance imaging.

BACKGROUND: During acute myocardial ischemia, myocardial postsystolic shortening (PSS) is considered as a sign of viability. In chronic left ventricular (LV) ischemic dysfunction, the value of PSS is less well established. In this study, PSS was compared with transmural extent of necrosis and contractile reserve in patients with chronic LV ischemic dysfunction. METHODS: A total of 25 patients (20 men, mean age: 63 +/- 8 years) with LV dysfunction (mean ejection fraction: 32 +/- 10%, range: 14%-47%) and stable coronary artery disease underwent rest color Doppler myocardial imaging, low-dose dobutamine echocardiography, and late enhancement gadolinium-magnetic resonance imaging. Strain (epsilon) curves were computed in 16 segments from color Doppler myocardial imaging sequences and were compared with transmural extent of necrosis and with contractile reserve. End-systolic epsilon was defined as epsilon value at aortic valve closure, peak epsilon (epsilon-peak) as maximal epsilon value during cardiac cycle, and time to epsilon-peak as time interval between aortic valve closure and epsilon-peak. PSS was considered when epsilon-peak occurred after aortic valve closure. RESULTS: Of 348 analyzable segments, 212 (61%) were graded as abnormal. In dysfunctional segments, PSS was more prevalent in transmural than in nontransmural infarcted segments (96% vs 50%, P < .001) and time to epsilon-peak was correlated to transmural extent of necrosis (r = 0.69, P < .0001). In nontransmurally infarcted segments, prevalence of PSS was similar in segments with or without contractile reserve (37% vs 45%, respectively). CONCLUSION: In chronic LV dysfunction, PSS is not a specific marker of viability. These results suggest strongly that delayed myocardial shortening may be associated to scarred segments.

Assessment of the physiologic significance of coronary disease with dipyridamole real-time myocardial contrast echocardiography. Comparison with technetium-99m sestamibi single-photon emission computed tomography and quantitative coronary angiography.

OBJECTIVES: The purposes of this study were to test whether quantitative real-time myocardial contrast echocardiography (RT-MCE) can detect coronary disease during pharmacologic stress and to compare this approach with single-photon emission computed tomography (SPECT). BACKGROUND: Assessing myocardial perfusion during stress is important for the diagnosis and risk stratification of patients with coronary disease. METHOD: Thirty-five patients referred for coronary angiography underwent RT-MCE and technetium-99m methoxyisobutylisonitrile (MIBI) SPECT at baseline and after 0.84 mg/kg dipyridamole. The modalities of RT-MCE and SPECT were analyzed both qualitatively and quantitatively. For this purpose, myocardial flow reserve was calculated from microbubble replenishment curves, and regional MIBI uptake was measured on circumferential profiles. Segments and vascular territories were categorized into five groups with increasing stenosis severity by quantitative coronary angiography. RESULTS: With dipyridamole, beta and A x beta increased in all but the highest stenosis severity group. The increase in beta and A x beta was significantly lower in territories supplied by stenotic arteries than in those supplied by arteries with <50% stenosis. Graded decreases in beta and A x beta reserves were noted with increasing stenosis severity. Using the cutoff value of 2.00 for beta reserve, quantitative RT-MCE correctly identified 97% of the territories supplied by significant stenoses and 82% of those supplied by normal arteries. In contrast, quantitative SPECT correctly identified only 71% of the territories supplied by significant stenoses and 81% of those supplied by normal arteries. CONCLUSIONS: This study shows that RT-MCE, with dipyridamole, can define the presence and severity of coronary disease in a manner that compares favorably with quantitative SPECT.

Heterogeneity of contrast effect during intermittent second harmonic myocardial contrast echocardiography in healthy patients.

Intermittent harmonic imaging with contrast is increasingly used to detect perfusion defects in patients with coronary disease. To achieve this, image homogeneity and the ability to visualize segments on the lateral and distal portions of the imaging field are important. The objective of this study was to evaluate whether the use of specific postprocessing algorithms, such as background subtraction with color coding and parametric display, allows for improved image homogeneity compared with conventional intermittent second harmonic imaging. For this purpose, 20 participants who were free of cardiac abnormalities and in whom myocardial perfusion should by definition be homogeneously distributed, underwent contrast echocardiography during the constant intravenous infusion of 1.0 +/- 0.3 mL/min of perfluorocarbon-enhanced sonicated dextrose albumin. End-systolic ECG-triggered images were obtained from the apical 4-chamber view at pulsing intervals of 300-ms 1, 3, 5, and 8 cardiac cycles. For analysis, each set of images was aligned, averaged, background subtracted, and color coded. Pulsing intervals versus videointensity plots were then generated for each pixel in the images and fitted to an exponential function to produce parametric images of beta (an index of microbubble velocity) and A (a measure of myocardial blood volume). The heterogeneity of the contrast effect was evaluated by computing the coefficients of variation in each image. Contrast heterogeneity was >20% with all 4 methods. However, it was greater in gray-scale second harmonic (39 +/- 13%) and color-coded (47 +/- 16%) images than in parametric images of beta and A (24 +/- 14 and 24 +/- 8%, respectively; both P <.05 vs gray-scale second harmonic and color-coded images). With all 4 methods, basal- and apical-lateral segments contributed most to image heterogeneity, albeit significantly less so with parametric imaging. In conclusion, our data indicate that myocardial opacification is frequently heterogeneous in healthy participants, particularly when using gray-scale second harmonic and background-subtracted with color-coding imaging. Parametric imaging allows reduction, albeit incomplete, of the heterogeneity of the contrast effect and therefore improves image quality.

Contribution of exercise-induced mitral regurgitation to exercise stroke volume and exercise capacity in patients with left ventricular systolic dysfunction.

BACKGROUND: Functional mitral regurgitation (MR) is common in patients with heart failure and left ventricular (LV) dysfunction, and its severity may vary over time, depending primarily on the loading conditions. Because dynamic changes in the severity of functional MR may affect forward stroke volume, we hypothesized that exercise-induced changes in MR severity influence the stroke volume response of patients with LV dysfunction to exercise, and hence their exercise capacity. METHODS AND RESULTS: Heart failure patients (n=25; mean age 53+/-12 years) with LV dysfunction underwent dynamic bicycle exercise at steady-state levels of 30%, 60%, and 90% of predetermined peak VO2. During each exercise level, right heart pressures, cardiac output, VO2, and MR severity were measured simultaneously. During exercise, MR severity, as evaluated by the ratio of MR jet over left atrium area, increased from 15+/-8% to 33+/-15%. Peak VO2, exercise-induced changes in stroke volume, and those in capillary wedge pressure correlated with the changes in MR (r=-0.55, -0.87, and 0.62, respectively, P<0.01). The changes in MR severity also correlated with those in end-diastolic (r=-0.75, P<0.01) and end-systolic (r=-0.72, P<0.01) sphericity indexes and those in the coaptation distance (r=0.86, P<0.01). CONCLUSIONS: Our data indicate that in patients with LV dysfunction, exercise-induced changes in MR severity limit the stroke volume adaptation during exercise and therefore contribute to limitation of exercise capacity.