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European Journal of Echocardiography Advance Access published online on May 25, 2008
European Journal of Echocardiography, doi:10.1093/ejechocard/jen169
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Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2008. For permissions please email: journals.permissions@oxfordjournals.org

Prognostic importance of quantitative echocardiographic evaluation in patients suspected of first non-massive pulmonary embolism

Jesper Kjaergaard1,2,*, Bente Krogsgaard Schaadt3, Jens Otto Lund3 and Christian Hassager2

1 Department of Cardiology, Copenhagen University Hospital Gentofte, Copenhagen, Denmark
2 Department of Cardiology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
3 Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Gentofte, Hellerup, Denmark

Received 19 February 2008; accepted after revision 26 April 2008.

* Corresponding author. Tel: +45 35453545; fax: +45 35452513. E-mail address: jesper.kjaergaard{at}rh.regionh.dk


   Abstract
Top
 Abstract
Introduction
 Methods
 Results
 Discussion
 Conclusions
 Funding
 References
 
Aims: Patients suspected of acute pulmonary embolism (PE) frequently undergo echocardiography as a part of the initial work-up. Prognostic implication of routine echocardiography in patients suspected of PE remain to be established.

Methods and results: Transthoracic echocardiography, including tissue Doppler imaging, was performed in 283 consecutive patients referred for ventilation/perfusion scintigraphy (V/Q scan) on suspicion of first non-massive PE. The prognostic information of quantitative measures of right ventricular (RV) size, function, and pressure was assessed. Patients with PE had a follow-up echocardiography after 1 year and changes in the parameters were assessed.

Patients with PE and normal V/Q scans had similar age-adjusted 1 year mortality [10 and 12%, NS (not significant)], although patients with indeterminate scans carried a poorer prognosis (16% survival, P = 0.0004). Among all patients left ventricular (LV) ejection fraction as well as shortening of the pulmonary artery (PA) acceleration time (a measure of RV after-load) was associated with increased mortality [hazard ratio (HR) = 0.84 per 10 ms increase, P < 0.0001].

In patients with confirmed PE, the PA acceleration time is predictive of event-free survival (all-cause mortality and heart failure hospitalizations) adjusted for LV ejection fraction, age, and sex (HR = 0.78 per 10 ms increase, P = 0.04).

Measures of regional myocardial function were not related to outcome in this study, regardless of presence of PE.

Conclusion: PA acceleration time and LV systolic function are independent predictors of mortality in patients suspected of PE, and are independent predictors of event-free survival in patients with confirmed PE.

Keywords: Pulmonary embolism; Perfusion scintigraphy; Echocardiography; Right ventricle; Ventricular function


   Introduction
Top
 Abstract
 Introduction
Methods
 Results
 Discussion
 Conclusions
 Funding
 References
 
Although not established as a diagnostic tool in the initial management of patients suspected of non-massive pulmonary embolism (PE),1 transthoracic echocardiography (TTE) provides data for risk stratification if PE is found,2,3 including identifying patients who might benefit from more aggressive treatment4 and is useful for the assessment of important differential diagnoses. Furthermore, the literature of the natural history of patients with non-massive PE is limited.5

Several quantitative echocardiographic measures of right ventricular (RV) function and pressure estimation have been validated in previous studies. Among measures of RV pressure, the pulmonary artery (PA) acceleration time is known to be inversely correlated to RV mean pressure,6–10 and this parameter has been shown to be a marker of proximal pulmonal emboli.11,12 Several echocardiographic parameters associated with increased risk in PE have been identified, but the prognostic implications of early TTE in patients suspected of PE has only been assessed in one earlier study,13 and the prognostic information available with the newer quantitative echocardiographic parameters has not been evaluated.

The present study assesses long-term survival and clinical course of patients suspected of first non-massive PE. Secondly, in patients in whom PE were present, a follow-up echocardiography was performed to assess the natural history of RV size, pressure, and function in patients treated for PE.


   Methods
Top
 Abstract
 Introduction
 Methods
Results
 Discussion
 Conclusions
 Funding
 References
 
The study population consisted a sample of 283 consecutive, clinically stable patients over the age of 18 years, referred for ventilation/perfusion scintigraphy (V/Q scan) to establish the diagnosis of first non-massive PE at the Copenhagen University Hospital Gentofte, and has previously been described.14 The local scientific ethical committee approved the study, reference no. KA 03035, and patients consented to the inclusion as well as follow-up. Information on medical history was obtained from the patients charts, blinded to the findings at the scintigraphy and echocardiography.

Ventilation/perfusion scintigraphy
V/Q scan was performed by injection of 110 MBq of 99mTechnetium macro-aggregated albumin (Lyo MAA, Malinckrodt, The Netherlands) and planar imaging was performed using a large field of view gamma camera (Genesys, ADAC Laboratories, Milpitas, CA, USA) during inhalation of 81mKrypton (dual isotope technique). Posterior, anterior, left and right posterior oblique scintigrams were acquired to a total of 106 counts or 300 s in each position. Two expert readers, blinded to the clinical and echocardiograhic information, classified the scans according to the revised PIOPED criteria15,16 and estimated the extent of perfusion defects in patients with PE as: small (1–25%), intermediate (25–49%) or severe (>50%).

Echocardiography
TTE was performed using a Philips SONOS 7500 system (Bothell, WA, USA) on the same day as the V/Q scan, median delay 1.6 h, maximal delay 5.6 h.

Measures of RV anatomy were RV end-diastolic diameter, measured in the parasternal long-axis view, and the ratio of RV to left ventricular (LV) end-diastolic diameter (RV/LV ratio) in the apical four-chamber view.17

Measures of RV pressure were the acceleration time of the RV outflow, i.e. the PA acceleration time, measured by pulsed wave Doppler with the sample volume positioned at the pulmonary valve in the parasternal short-axis view.11 A shortened PA acceleration time is inversely related to increasing PA pressure.10 RV to right atrial pressure gradient was estimated by continuous wave Doppler as the maximal pressure gradient of the tricuspid regurgitation (TR).18 Presence of abnormal motion of the interventricular septum in diastole as a sign of RV diastolic pressure exceeding LV diastolic pressure was also recorded.

Measures of RV function included the fractional shortening of the RV outflow tract diameter measured by M-mode echocardiography in short-axis view at the level of the aortic valve19 and the fractional shortening of the RV in the parasternal long axis.17 In the apical four-chamber view the tricuspid annular plane systolic excursion (TAPSE) and the peak systolic velocity (s') was measured by M-mode and pulsed wave tissue Doppler imaging (TDI), respectively, at the junction of the RV free wall and tricuspid annular plane. A colour TDI cine loop of three consecutive cardiac cycles of the RV free wall was acquired in the apical four-chamber view and stored for off-line analysis. Average frame rate was 120 ± 12 frames/s. Using the Philips® Q-lab software®, version 2.0 (Bothell, WA, USA), an anatomical M-mode line was placed in end-systole, and the peak systolic velocity and strain of the basal and mid-third of the RV free wall were recorded. Acquisition of images and subsequent analysis of echocardiographic imaging was performed blinded to the findings at the V/Q scan.

Electrocardiographic data
Electrocardiographic signs of RV strain, defined as the presence of right bundle branch block, SIQIIITIII-sign or negative T-waves in V1–V3 on electrocardiograms were recorded if ECG performed within 24 h of the V/Q scan was available.

Follow-up
Follow-up was done via data linkage to the Central Person Register at the end of February 2007 for the assessment of all-cause mortality at 1 year and at end of follow-up (median follow-up time 3.1 years). One patient had emigrated prior to inclusion, and was excluded from the present analysis as no survival data could be obtained, leaving 282 patients for further analysis.

A sub-group analysis in patients with PE was planned, and due to an expected limited number of deaths in the cohort at 1 year, a predefined secondary end-point of heart failure hospitalization or death was assessed from data linkage to the Danish administrative hospital registry at 1 year.

All patients alive were contacted by telephone 1 year after their inclusion in study (median 365 days, inter-quartile range: 3 days), and a structured interview was performed including information of current functional capacity, defined as New York Heart Association class, and hospitalizations after discharge from hospital. At the end of the interview, patients with PE were offered a clinical visit, including TTE and ECG. TDI data were not available at follow-up.

Statistical analysis
Data are presented as mean ± SD, differences were tested by paired or un-paired t-test as appropriate. Changes in paired categorical data were evaluated by McNemar’s test. Age-adjusted Kaplan–Meier plots are presented for univariate survival analysis at 1 year and at end of follow-up, differences in survival rates were tested by log-rank test. A Cox proportional hazard model for multivariable analysis was used for univariate and multivariate modelling (backward elimination), after checking for assumptions of proportionality, linearity, and lack of interactions. As the PA acceleration time has been shown to be related to heart rate,20 all analyses were repeated correcting of heart rate. All computations were done using the SAS statistical software, version 9.12, SAS Institute Inc., Cary, NC, USA.


   Results
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 Abstract
 Introduction
 Methods
 Results
Discussion
 Conclusions
 Funding
 References
 
Mean age in the population studied was 68 ± 16 years, and 53% were female. Chronic obstructive pulmonary disease was present in 52 (19%) patients at baseline, and was significantly more prevalent in patients with indeterminate V/Q scans than in patients with normal scans or PE, 30 vs. 10 and 12%, P = 0.0002, although presence of chronic obstructive pulmonary disease had no effect on overall mortality, log-rank test P = 0.17. No differences in blood pressure, heart rate, symptoms suggestive of or prevalence of risk factors associated with PE, was found between the three groups of patients defined by the findings at V/Q scan.14

Follow-up on patients referred for ventilation/perfusion scintigraphy
Overall 46 (16%) patients had died before 1 year follow-up could be obtained, and in 14 patients no interview could be performed: nine patients refused, two were unable to participate due to medical conditions, and we were unable to contact three patients, Figure 1.


Figure 1
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  		Figure 1 Flow chart of 283 patients admitted on suspicion of first non-massive pulmonary embolism and 1 year telephone interview and echocardiography in patients diagnosed with pulmonary embolism.

 
Among 222 patients available for the follow-up interview, 33 (37%), 31 (36%), and 20 (44%), not significant (NS) patients with normal, indeterminate scans, and PE, respectively, had been re-admitted to hospital. Of these hospitalizations 15 (45%), 19 (61%), and 13 (65%), NS had been for heart failure or dyspnoea. The median improvement of a functional class was found in all three groups, P < 0.0001 for all groups, with no differences between groups.

Age-adjusted mortality rate in patients with indeterminate V/Q scans at inclusion were significantly higher than in patients with normal V/Q scans or PE at 1 year follow-up, 16 vs. 12 or 10%, P < 0.0004, with similar long-term trends, 41 vs. 20 or 23%, P < 0.0001, respectively, Figure 2. When stratifying the population by PA acceleration time, a significantly higher age-adjusted mortality rates in patients with PA acceleration time ≤120 ms was found, P < 0.0001.


Figure 2
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  		Figure 2 Mortality in patients suspected of first non-massive pulmonary embolism by findings at ventilation/perfusion scintigraphy, top panel, and pulmonary artery (PA) acceleration time, bottom panel. Tertiles of PA acceleration time correspond to mean pulmonary artery pressures of <19, 19–31, and >31 mmHg, for the first, second and third tertile, respectively.6 Differences in mortality assessed by log-rank test at 1 year (vertical line) and at end of follow-up.

 
The predictive information from baseline echocardiographic parameters on long-term survival is shown in Table 1, showing that PA acceleration time, TAPSE, and LV ejection fraction were strongly associated with mortality in the univariate models, P < 0.0001. No interaction with results of V/Q scans was identified, and in sub-group analysis by result of the V/Q scan similar trends were found, data not shown. A multivariate model showed that PA acceleration time and LV ejection fraction had incremental prognostic information, P = 0.006 and 0.02, respectively, even when adjusted for the effect of age and sex, Table 1. To adjust for the impact of heart rate on PA acceleration time the analysis was repeated indexing the PA acceleration time to heart rate, and by including heart rate in the multivariate analysis. Both analyses yielded similar results as presented for the un-adjusted measure, data not shown.


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  		Table 1 Proportional hazard (mortality) associated with quantitative echocardiographic measurements of right ventricular size, pressure, and function and left ventricular ejection fraction in all patients suspected of first non-massive pulmonary embolism, N = 282. Multivariate model included parameters with a P-value < 0.1 in the univariate analysis, and age and sex

 
When analysis in the sub-group of patients in whom no PE on V/Q scan was found, N = 225, the PA acceleration time was still predictive of mortality [HR (hazard ratio) = 0.79, P < 0.0001 per 10 ms increase].

Echocardiographic follow-up in patients with pulmonary embolism
Causes of death during the first year were cardiovascular in two cases, cancer in two patients and unknown in four patients. Forty-five (78%) patients of the 58 patients diagnosed with PE, completed the telephone interview, and 41 patients agreed to the follow-up echocardiography as two patients refused the echocardiography and two patients were unable to participate for medical reasons, Figure 1.

In univariate analysis in patients with PE an increased RV to LV diameter ratio, a reduced PA acceleration time, TAPSE or LV ejection fraction seemed predictive event-free survival within the first year after first non-massive PE. Only PA acceleration time and LV ejection fraction were independently related to event-free mortality, when adjusting for age and sex, Table 2. RV free wall mid-wall strain or other TDI-based parameters were not associated with all-cause mortality or event-free survival, data not shown. No differences in survival or event-free survival were found when stratifying the PE population by size of perfusion defects at the baseline echocardiography, data not shown.


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  		Table 2 Univariate analysis of baseline echocardiography and the relation to event-free survival (all-cause mortality or heart failure related hospitalization) in 58 patients with first non-massive pulmonary embolism. Multivariate model included parameters with a P-value < 0.1 in the univariate analysis, and age and sex

 
On the echocardiographic 1 year follow-up, no changes in blood pressure, 136 ± 26 / 83 ± 16 vs. 135 ± 22 / 80 ± 10 mmHg, NS, or prevalence of peripheral oedema, 13 (22%) vs. 11 (27%), NS, were seen. The prevalence of negative T-waves in V1–V3 decreased significantly, 29 vs. 3% P = 0.004. Compared with baseline, PA acceleration time increased from 89 ± 23 to 116 ± 31 ms, P < 0.0001 and measures of global RV systolic function (i.e. RV fractional shortening, RV outflow tract fractional shortening, and TAPSE) improved, Table 3. In Figure 3 the individual changes in echocardiographic parameters found to be predictive of outcome in the multivariate model are shown, illustrating a reduction in RV after-load and unchanged LV ejection fraction.


Figure 3
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  		Figure 3 Changes in quantitative echocardiographic measures found to be predictive of outcome in the multivariate model (Table 2) in patients diagnosed with first non-massive pulmonary embolism compared with finding at 1 year follow-up. The pulmonary artery (PA) acceleration time, top panel (corresponding to a mean pulmonary pressure of 33 ± 12 mmHg at baseline and 23 ± 10 mmHg at follow-up6) and left ventricular (LV) ejection fraction, bottom panel. Error bars represent mean ± SD for patients with measurements available at baseline and at follow-up. Filled circles represent patients dying within 1 year from baseline, P-value refers to changes from baseline to follow-up examination.

 


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  		Table 3 Electrocardiographic and echocardiographic findings at baseline and after 1 year in patient diagnosed with pulmonary embolism, N = 41

 

   Discussion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
Conclusions
 Funding
 References
 
In patients suspected of first non-massive PE, long-term survival is similar in patients in whom PE is confirmed and patients with normal V/Q scans, whereas patients with indeterminate V/Q scans carry a poorer prognosis. The PA acceleration time as a measure of RV after-load and LV ejection fraction hold significant prognostic information over the V/Q scan. At 1 year follow-up, the PA acceleration time and global RV systolic function are improved and normalized in patients with PE.

Changes in the pulmonary blood flow through the pulmonary valve have previously been shown to occur in pulmonary hypertension.6,8,21 A mid-systolic peak in outflow velocity is seen in mid-systole in patients with normal pulmonary resistance, and with increasing resistance, the blood accelerates rapidly to its peak earlier in systole, thereby shortening the time interval from onset to peak flow rate, i.e. PA acceleration time.8 An inverse log-linear relation of PA acceleration time and pulmonary pressures has been found, with the closest correlation with mean PA pressure as used for estimation of RV pressure in the present study.6

Follow-up in patients referred for ventilation/perfusion scintigraphy
The present report consolidates earlier findings that the survival is similar in patients in whom PE is confirmed and patients in whom PE is excluded,13,22 and adds that the sub-group of patients where a definite diagnosis cannot be made by V/Q scan has a significantly worse prognosis and may thus be eligible for further evaluation. Indeterminate V/Q scans are more frequent in elderly patients and in patients with chronic obstructive pulmonary disease or emphysema,23 which may be a part of the reason for the increased mortality found in the present study. Chronic obstructive pulmonary disease was more prevalent in this group in the present study, but as baseline demographics and clinical finding were similar in the groups, the echocardiographic findings may still be relevant parameters for the assessment of risk in this heterogeneous group of patients.

Univariate analysis showed that several quantitative measures of RV pressure and global systolic function were related to mortality, whereas as the novel tissue Doppler based measures of regional RV myocardial function seem to be of minor importance in risk assessment. The multivariate survival analysis suggested that even though presence of PE is not a significant predictor of mortality, echocardiographic findings suggestive of increased RV after-load and LV heart failure are important risk factors in these patients. Other echocardiographic indices of global RV systolic function were also related to outcome, but PA acceleration time was the stronger predictor of mortality. Pulmonary hypertension in heart failure has also been shown to carry significant prognostic information.24,25 Both the TR gradient and the PA acceleration time have been shown to be measures of RV pressure, and the authors speculated that PA acceleration time may be the stronger predictor of mortality in part due this parameter being technically easy to obtain.

LV ejection fraction as an essential parameter in the use of echocardiography in patients admitted with dyspnoea is widely accepted,26 and the present study adds that this parameter, along with evaluation of RV overload is useful predictor of outcome in patients suspected of PE.

Outcome in patients with pulmonary embolism
The overall mortality in patients with PE found in the present study was similar to previous studies in patients with non-massive PE.22,27,28 RV dysfunction has been associated with adverse outcome in patients with PE,3,28,29 although other studies were unable to identify predictive echocardiographic factors,30,31 as found in the present study. However, acknowledging that the sample size for the sub-group analysis in this prospective study would limit the power of stratified analysis, we predefined a secondary end-point of heart failure related hospitalization and death. Several of the quantitative echocardiographic parameters of RV pressure and global function were found to be predictive of event-free 1 year survival, the PA acceleration time and LV ejection fraction were found to be the stronger predictors of outcome.

The novel tissue Doppler-based measures of myocardial deformation, previously shown to be reduced in PE patients,14 were not related to outcome, even though isolated mid-wall hypokinesis is thought to be a specific feature of larger PE.32 Obtaining imaging for evaluation of regional myocardial deformation and deformation rate is challenging, and a previous study has identified higher levels of variability than found in spectral Doppler and 2D-based imaging.33

Echocardiographic measures of RV overload, previously shown to be related not only to the presence of PE, but also to the extent of embolism, improved during the 1 year follow-up. TAPSE as a measure of global RV systolic function is related to the presence and extent of PE,5,14 and has recently been suggested as a sensitive marker of persisting RV dysfunction.5 Interestingly, longitudinal RV dysfunction may persist beyond the usual time for thrombi to resolve,5,34 whereas TR pressure gradient, a measure of RV systolic pressure, may be closely related to resolution of perfusion defects.27 The underlying mechanism remains to be established, but studies do suggest that follow-up evaluation of RV dysfunction 3–6 months of the diagnosis cannot exclude further recovery of function.5

The PA acceleration time is shortened with RV pressure overload, and has been shown be a diagnostic marker of PE, and in particular proximal thrombi.11,12,14 Interestingly the PA acceleration time was the more predictive parameter in the multivariate analysis. If confirmed in future studies in patients suspected of non-massive PE, this parameter seems to be useful not only in the initial diagnostic work-up of these patients,14 but may also provide useful prognostic information.


   Conclusions
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusions
Funding
 References
 
Quantitative measures of global and regional RV function may add prognostic information in patients suspected of non-massive PE.

PA acceleration time, as a measure of RV after-load, adds incremental prognostic information on top of information of V/Q scan. Significant improvement in echocardiographic and electrocardiographic markers of RV dysfunction is seen at 1 year follow-up, and among measures of RV pressure and function, the PA acceleration time seems to be the stronger predictor of event-free survival in patients with confirmed PE.


   Funding
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusions
 Funding
References
 
The Danish Heart Foundation supported the Research fellowship of Dr J.K. (grant no. 04-10-B109-A166-22192).


   Acknowledgements
 
Ane Loof Johansen, RN, and Marianne Nielsen, RN, are acknowledged for their contributions in the inclusion and follow-up of the patients in this study.

Conflict of interest: there are no potential conflicts of interest.


   References
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 Introduction
 Methods
 Results
 Discussion
 Conclusions
 Funding
 References
 

  1. Goldhaber SZ, Elliott CG. Acute pulmonary embolism: Part II: risk stratification, treatment, and prevention. Circulation (2003) 108:2834–8.[Free Full Text]
  2. Kucher N, Rossi E, De RM, Goldhaber SZ. Prognostic role of echocardiography among patients with acute pulmonary embolism and a systolic arterial pressure of 90 mm Hg or higher. Arch Intern Med (2005) 165:1777–81.[Abstract/Free Full Text]
  3. Kasper W, Konstantinides S, Geibel A, Tiede N, Krause T, Just H. Prognostic significance of right ventricular afterload stress detected by echocardiography in patients with clinically suspected pulmonary embolism. Heart (1997) 77:346–9.[Abstract/Free Full Text]
  4. Konstantinides S, Geibel A, Heusel G, Heinrich F, Kasper W. Heparin plus alteplase compared with heparin alone in patients with submassive pulmonary embolism. N Engl J Med (2002) 347:1143–50.[Abstract/Free Full Text]
  5. Chung T, Emmett L, Mansberg R, Peters M, Kritharides L. Natural history of right ventricular dysfunction after acute pulmonary embolism. J Am Soc Echocardiogr (2007) 20:885–94.[CrossRef][Web of Science][Medline]
  6. Kitabatake A, Inoue M, Asao M, Masuyama T, Tanouchi J, Morita T, et al. Noninvasive evaluation of pulmonary hypertension by a pulsed Doppler technique. Circulation (1983) 68:302–9.[Abstract/Free Full Text]
  7. Kosturakis D, Goldberg SJ, Allen HD, Loeber C. Doppler echocardiographic prediction of pulmonary arterial hypertension in congenital heart disease. Am J Cardiol (1984) 53:1110–5.[CrossRef][Web of Science][Medline]
  8. Isobe M, Yazaki Y, Takaku F, Koizumi K, Hara K, Tsuneyoshi H, et al. Prediction of pulmonary arterial pressure in adults by pulsed Doppler echocardiography. Am J Cardiol (1986) 57:316–21.[CrossRef][Web of Science][Medline]
  9. Marchandise B, De BB, Delaunois L, Kremer R. Noninvasive prediction of pulmonary hypertension in chronic obstructive pulmonary disease by Doppler echocardiography. Chest (1987) 91:361–5.[CrossRef][Web of Science][Medline]
  10. Marangoni S, Quadri A, Dotti A, Scalvini S, Volterrani M, Schena M, et al. Noninvasive assessment of pulmonary hypertension: a simultaneous echo-Doppler hemodynamic study. Cardiology (1988) 75:401–8.[Web of Science][Medline]
  11. Kurzyna M, Torbicki A, Pruszczyk P, Burakowska B, Fijalkowska A, Kober J, et al. Disturbed right ventricular ejection pattern as a new Doppler echocardiographic sign of acute pulmonary embolism. Am J Cardiol (2002) 90:507–11.[CrossRef][Web of Science][Medline]
  12. Torbicki A, Kurzyna M, Ciurzynski M, Pruszczyk P, Pacho R, Kuch-Wocial A, et al. Proximal pulmonary emboli modify right ventricular ejection pattern. Eur Respir J (1999) 13:616–21.[Abstract]
  13. van Beek EJ, Kuijer PM, Buller HR, Brandjes DP, Bossuyt PM, ten Cate JW. The clinical course of patients with suspected pulmonary embolism. Arch Intern Med (1997) 157:2593–8.[Abstract/Free Full Text]
  14. Kjaergaard J, Schaadt BK, Lund JO, Hassager C. Quantitative measures of right ventricular dysfunction by echocardiography in the diagnosis of acute nonmassive pulmonary embolism. J Am Soc Echocardiogr (2006) 19:1264–71.[CrossRef][Web of Science][Medline]
  15. Sostman HD, Coleman RE, DeLong DM, Newman GE, Paine S. Evaluation of revised criteria for ventilation-perfusion scintigraphy in patients with suspected pulmonary embolism. Radiology (1994) 193:103–7.[Abstract/Free Full Text]
  16. Gottschalk A, Sostman HD, Coleman RE, Juni JE, Thrall J, McKusick KA, et al. Ventilation-perfusion scintigraphy in the PIOPED study. Part II. Evaluation of the scintigraphic criteria and interpretations. J Nucl Med (1993) 34:1119–26.[Abstract/Free Full Text]
  17. Lang RM, Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, et al. Recommendations for chamber quantification: a report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr (2005) 18:1440–63.[CrossRef][Web of Science][Medline]
  18. Quinones MA, Otto CM, Stoddard M, Waggoner A, Zoghbi WA. Recommendations for quantification of Doppler echocardiography: a report from the Doppler Quantification Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography. J Am Soc Echocardiogr (2002) 15:167–84.[CrossRef][Web of Science][Medline]
  19. Lindqvist P, Henein M, Kazzam E. Right ventricular outflow-tract fractional shortening: an applicable measure of right ventricular systolic function. Eur J Echocardiogr (2003) 4:29–35.[Abstract/Free Full Text]
  20. Chan KL, Currie PJ, Seward JB, Hagler DJ, Mair DD, Tajik AJ. Comparison of three Doppler ultrasound methods in the prediction of pulmonary artery pressure. J Am Coll Cardiol (1987) 9:549–54.[Abstract]
  21. Hirschfeld S, Meyer R, Schwartz DC, Kofhagen J, Kaplan S. The echocardiographic assessment of pulmonary artery pressure and pulmonary vascular resistance. Circulation (1975) 52:642–50.[Abstract/Free Full Text]
  22. Miniati M, Monti S, Bottai M, Scoscia E, Bauleo C, Tonelli L, et al. Survival and restoration of pulmonary perfusion in a long-term follow-up of patients after acute pulmonary embolism. Medicine (Baltimore) (2006) 85:253–62.[CrossRef][Medline]
  23. Calvo-Romero JM, Lima-Rodriguez EM, Bureo-Dacal P, Perez-Miranda M. Predictors of an intermediate ventilation/perfusion lung scan in patients with suspected acute pulmonary embolism. Eur J Emerg Med (2005) 12:129–31.[CrossRef][Medline]
  24. Ghio S, Gavazzi A, Campana C, Inserra C, Klersy C, Sebastiani R, et al. Independent and additive prognostic value of right ventricular systolic function and pulmonary artery pressure in patients with chronic heart failure. J Am Coll Cardiol (2001) 37:183–8.[Abstract/Free Full Text]
  25. Kjaergaard J, Akkan D, Iversen KK, Kjoller E, Kober L, Torp-Pedersen C, et al. Prognostic importance of pulmonary hypertension in patients with heart failure. Am J Cardiol (2007) 99:1146–50.[CrossRef][Web of Science][Medline]
  26. Gustafsson F, Torp-Pedersen C, Brendorp B, Seibaek M, Burchardt H, Kober L. Long-term survival in patients hospitalized with congestive heart failure: relation to preserved and reduced left ventricular systolic function. Eur Heart J (2003) 24:863–70.[Abstract/Free Full Text]
  27. Ribeiro A, Lindmarker P, Johnsson H, Juhlin-Dannfelt A, Jorfeldt L. Pulmonary embolism: one-year follow-up with echocardiography doppler and five-year survival analysis. Circulation (1999) 99:1325–30.[Abstract/Free Full Text]
  28. Ribeiro A, Lindmarker P, Juhlin-Dannfelt A, Johnsson H, Jorfeldt L. Echocardiography Doppler in pulmonary embolism: right ventricular dysfunction as a predictor of mortality rate. Am Heart J (1997) 134:479–87.[CrossRef][Web of Science][Medline]
  29. Grifoni S, Olivotto I, Cecchini P, Pieralli F, Camaiti A, Santoro G, et al. Short-term clinical outcome of patients with acute pulmonary embolism, normal blood pressure, and echocardiographic right ventricular dysfunction. Circulation (2000) 101:2817–22.[Abstract/Free Full Text]
  30. Vieillard-Baron A, Page B, Augarde R, Prin S, Qanadli S, Beauchet A, et al. Acute cor pulmonale in massive pulmonary embolism: incidence, echocardiographic pattern, clinical implications and recovery rate. Intensive Care Med (2001) 27:1481–6.[CrossRef][Web of Science][Medline]
  31. Mansencal N, Joseph T, Vieillard-Baron A, Qanadli SD, Jondeau G, Lacombe P, et al. Comparison of different echocardiographic indexes secondary to right ventricular obstruction in acute pulmonary embolism. Am J Cardiol (2003) 92:116–9.[CrossRef][Web of Science][Medline]
  32. McConnell MV, Solomon SD, Rayan ME, Come PC, Goldhaber SZ, Lee RT. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol (1996) 78:469–73.[CrossRef][Web of Science][Medline]
  33. Kjaergaard J, Korinek J, Belohlavek M, Oh JK, Sogaard P, Hassager C. Accuracy, reproducibility, and comparability of Doppler tissue imaging by two high-end ultrasound systems. J Am Soc Echocardiogr (2006) 19:322–8.[CrossRef][Medline]
  34. Ribeiro A, Lindmarker P, Johnsson H, Juhlin-Dannfelt A, Jorfeldt L. Pulmonary embolism: a follow-up study of the relation between the degree of right ventricle overload and the extent of perfusion defects. J Intern Med (1999) 245:601–10.[CrossRef][Web of Science][Medline]

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