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Descripitive patterns of severe chronic pulmonary hypertension by chest radiography

Respiratory Medicine (2005)99,329–

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Descriptive patterns of severe chronic pulmonary hypertension by chest radiography

T oru Satoh ?,Shingo Kyotani,Yoshiaki Okano,Norifumi Nakanishi,Takeyoshi Kunieda

Department of Medicine,Division of Cardiology and Pulmonary Circulation,

National Cardiovascular Center ,5-7-1Fujishirodai,Suita,Osaka 565-8565,Japan

Received 9January 2004;accepted 13August 2004

Summary Background:To ?nd chest roentgenographic (CXR)features to help differentiate two representative diseases with severe chronic pulmonary hyperten-sion (PH).

Study subjects:Thirty-six consecutive patients with chronic thromboembolic PH (CTEPH),38with primary PH (PPH),and 37with left heart disease and PH.

Methods:CXRs were reviewed about 6features (left 2nd arc protrusion,right descending pulmonary artery diameter (rPAD),cardiothoracic ratio (CTR),right 2nd arc width,avascular area and pleural abnormality).Hemodynamic data and the degree of tricuspid regurgitation (TR)on echocardiography were compared with CXR ?ndings.

Results:The diagnostic pattern of CTEPH was the presence of one of two ?ndings,an avascular area or marked rPAD (420mm)together with pleuritic change.The diagnostic pattern of PPH was one of the two features;without pleuritic abnormality,marked left 2nd arc protrusion (410mm)or moderate left 2nd arc protrusion (5–10mm)with marked rPAD (o 20mm).The sensitivity for the diagnosis of CTEPH among the three diseases was 78%and speci?city was 92%.The sensitivity for the diagnosis of PPH was 45%and speci?city was 88%.CTR and right 2nd arc width were related to the degree of TR in CTEPH and PPH.

Conclusions:Characteristic roentgenographic ?ndings can help differentiate two frequent diseases associated with chronic pulmonary hypertension and re?ect the severity of disease.

Introduction

Primary and chronic thromboembolic pul-monary hypertension (PH)are two major diseases

KEYWORDS

Chronic

thromboembolic pulmonary hypertension;

Primary pulmonary hypertension;Pulmonary hypertension;Chest

roentogenography

?Corresponding author .Cardiopulmonary Division,Department

of Medicine,Keio University School of Medicine,Shinanomachi 35,Shinjukuku,Tokyo 160-8582,Japan.Tel.:+81-3-3353-1211;fax:+81-3-3353-2502.

E-mail address:tsatoh@cpnet.med.keio.ac.jp (T .Satoh).

associated with severe chronic PH.These two representative diseases have very similar clinical presentation and results of various laboratory tests,but are very different in their treatment.Patients with primary pulmonary hypertension (PPH)are beginning to have a better prognosis with the introduction of continuous epoprostenol infusion 1,2and many patients with chronic thromboembolic pulmonary hypertension (CTEPH)can be cured by pulmonary thromboendarterectomy.3In view of their different pathologic processes,there may be characteristic chest radiographic ?ndings in each entity that can be used to help differentiate them,though some features are shared.Simple radio-graphic recognition would lead to early diagnostic deduction of the disease,reducing the cost and relieving the burden on the patients from unneces-sary examinations.

Chest radiographic ?ndings characteristic in primary 4,5and thromboembolic 6PH have been reported in detail separately.Differentiation of the two entities by chest roentogenography was thought dif?cult in several series 7,8but was pursued vigorously with somewhat satisfactory results by Anderson et al.9They,however ,included acute and chronic varieties in their cases of thromboembolic PH,and failed to pick up impor-tant features such as proximal pulmonary arterial dilatation caused by severe intimal thickening in the chronic cases.

We,therefore,evaluated chest roentgenograms to identify characteristic ?ndings in 38consecutive patients with PPH and 36with CTEPH with de?nite ?nal diagnosis and hemodynamic measurement.We also evaluated chest roentgenograms in patients with left heart disease and PH to differentiate PPH,CTEPH and secondary PH due to left heart disease.We then compared the ?ndings in these three categories and de?ned the diagnostic patterns for the former two PH diseases.In addition,the variables measured in roentgenograms were quan-ti?ed and compared with hemodynamic parameters to relate the roentgenographic ?ndings to the severity of disease.

Methods

Study patients

Patients from the three categories were studied retrospectively.Patients with CTEPH consisted of 36consecutive patients who were diagnosed by radionuclide perfusion lung scan,computed tomo-graphy and pulmonary angiography with hemody-namic measurement.8All patients had more than moderate hypoxia and multiple perfusion defects on radionuclide perfusion lung scan,suggesting central type pulmonary embolism.Patients with PPH were 38consecutive patients with hemody-namic measurement by right heart catheterization who were de?ned as having PH unexplained by any secondary causes,based on the criteria of the National Institutes of Health registry on PPH.10The third group consisted of patients with left heart disease and PH who had equivalent age,sex and pulmonary pressure as the group of patients with CTEPH.They included 23patients with valvular heart disease and 12with idiopathic cardiomyo-pathy,which were diagnosed by echocardiography and cardiac catheterization.Detailed patient char-acteristics are presented in Table 1.Patients with PPH were younger ,had a larger proportion of female patients and had higher pulmonary artery pressure.

Chest roentgenographic evaluation

The radiographs were taken by computed radio-graphy (FCR AC-3,Fuji Medical Systems,Co.,Ltd.,Tokyo,Japan).T ube voltage was 120kV ,tube current was 200mA and phototimer was 30–40ms.Films were exposed during suspension of respira-tion at deep inspiration.The focus-?lm distance in the PA projection was 1.8m with the patient upright.

T wo of the authors (T .S.and S.K.)evaluated the chest roentgenographs retrospectively without knowing the patient names.The measured

Table 1Patient characteristics.Disease Number Age (y/o)Sex (m/f)Weight (kg)MPA (mm Hg)PVR (unit)PCWP (mm Hg)CTEPH 365271419/175579457141378873PPH 383571513/255479617121779976LHD

56715

21/16

56710

38714

472

2178

CTEPH:chronic thromboembolic pulmonary hypertension;LHD:left heart disease;m/f:male/female;mPA:mean pulmonary artery pressure;Number:number of patients;PCWP:pulmonary capillary wedge pressure;PPH:primary pulmonary hypertension;PVR:pulmonary vascular resistance;y/o:years old.Some values are presented as mean 7SD .

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variables in study patients were compared between the two authors by Student’s t-test.There were no signi?cant differences between the two for all the measured variables.Therefore,the two measured values were averaged and used for the following evaluation.The chest roentgenographs evaluated were taken within one week of cardiac catheter-ization and hemodynamic measurement.The mea-sured variables are demonstrated in Fig.1:(1)The degree of left2nd arc protrusion:the distance from the farthest protruding point of the left2nd arc perpendicular to the line between the lowest point of the left1st arc and the uppermost point of the left3rd arc.(2)The width of the right descending pulmonary artery.(3)The cardiothoracic ratio:the percent ratio of the cardiac silhouette width to the thoracic width.(4)The width of the right2nd arc: the distance from the farthest right point of the right2nd arc perpendicular to the vertebral body.

(5)Avascular area:paucity of vasculature in contrast to vasculature in the contralateral lung ?eld.(6)Pleural sign:old pleuritic shadow pre-sumably due to pulmonary infarction. Hemodynamic and echocardiographic evaluation

Right heart catheterization was performed through the right internal jugular vein or the right femoral vein.The mean right atrial pressure and the mean pulmonary artery pressure were compared with the chest roentgenographic?ndings.Echocardiography was performed within one week of cardiac cathe-terization.The degree of tricuspid regurgitation (TR)was graded from1to4according to observa-tion in the parasternal short axis and apex4-chamber views based on the standard criteria11,for comparison with the?ndings of chest X-rays. Statistical analysis

Chest roentgenographic features were compared among the three groups by Scheffe’s multiple comparison analysis or w2-test.Sensitivity was calculated by dividing the number of true positive cases by the number of positive cases.Speci?city was calculated as dividing the number of true negative cases by the number of negative cases among the three groups.

Results

Average values of and frequency of presence of each roentgenographic?nding

Detailed results are presented in Table2.(1)The degree of left2nd arc protrusion was greater in PPH.(2)The right descending pulmonary artery was wider in chronic thromboembolic and primary PH than in left heart disease.(3)Pleural sign was recognized more frequently in CTEPH and left heart disease.(4)The cardiothoracic ratio(CTR)was not different among the three.(5)An avascular area was only found in CTEPH.(6)The width of the right 2nd arc was not statistically signi?cantly different among the three groups.

Differential diagnosis of chronic thromboembolic and primary pulmonary hypertension

1.CTEPH:The presence of avascular area(Fig.2) was only found in this entity and in15out of the36 patients.It was decided as the?rst diagnostic pattern.As the right descending pulmonary artery was more prominent in diameter and the pleuritic signs were seen more frequently in this group,the next diagnostic pattern for CTEPH was the width of the right descending pulmonary artery diameter more than20mm together with pleuritic abnorm-ality(Fig.3).It was seen in13out of the remaining 21patients without avascular area in the throm-boembolic group,5out of38patients with PPH and

Figure1Evaluated signs and measured variables in chest

roentgenographs.Following six signs and measurements

were determined in chest roentgenographs taken with

the patient standing.(1)Degree of left2nd arc

protrusion.(2)Right descending pulmonary artery dia-

meter.(3)Cardiothoracic ratio.(4)Width of right2nd

arc.(5)Avascular area.(6)Pleural sign.For details see

text.

Diagnosis of pulmonary hypertension by CXR331

1out of 37patients with left heart disease.If we de?ne owning one of these 2roentgenographic patterns as the diagnostic features for CTEPH,the sensitivity among these 3diseases was 78%and the speci?city was 92%.The positive predictive value was 82%and the negative predictive value was 97%(Table 3).

2.PPH :Left second arc protrusion of more than 10mm (Fig.4)was found in 3patients in CTEPH,7in PPH and 3in left ventricular disease.Left second arc protrusion of more than 5mm with right descending pulmonary arterial diameter more than

20mm without pleural abnormality was found 3in thromboembolism,10in PPH and no patient in left ventricular disease and pulmonary hypertension.When the presence of one of these two roentgeno-graphic ?ndings was de?ned as the diagnostic pattern for PPH,the sensitivity among these three disease groups was 45%and the speci?city 88%.The positive predictive value was 65%and the negative predictive value 88%.

Table 2

Chest roentgenographic ?ndings.

CTEPH

PPH LHD lt2ndArc (mm) 4.873.6 6.673.4* 3.475.1rtPA (mm)2176*2074*1673CTR (%)

5476587135979rt2ndArc (mm)287123071534717Avascular area 15/36*0/380/37Pleuritic scar

21/36*

12/38

19/37*

CTEPH:chronic thromboembolic pulmonary hypertension;CTR:cardiothoracic ratio;LHD:left heart disease;lt2ndArc:degree of left second arc protrusion;PPH:primary pulmonary hypertension;rtPA:diameter of right descending pulmonary artery;rt2ndArc:width of right 2nd arc.Values for ?rst 4items are presented as mean 7SD .Avascular area and pleuritic scar are presented as the frequency of the presence of each ?nding.See text for details.*P o

0.05.

Figure 2Avascular area.Chest X-ray of 45-year-old man.Mean pulmonary artery pressure was 38mm Hg.Vascular markings in the left upper and middle lung ?elds are sparse compared to those in the corresponding right

lung.

Figure 3Marked right descending pulmonary artery dilatation with pleural abnormality.Chest X-ray of 44-year-old woman.Mean pulmonary artery pressure was 43mm Hg.There are bilateral lower pleural changes with enlarged right descending pulmonary artery diameter of 20mm.

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Mean pulmonary artery pressure and roentgenographic ?ndings

The relations of mean pulmonary artery pressure with left 2nd arc protrusion,and with cardiothor-acic ratio,among the three groups are depicted in Fig.6.The degree of left 2nd arc protrusion was signi?cantly correlated with mean pul-monary artery pressure only in the left heart disease group.The cardiothoracic ratio showed signi?cant correlations with mean pulmonary ar-tery pressure in the CTEPH and left heart disease group (Fig.5).

Degree of TR and roentgenographic ?ndings

The degree of TR was signi?cantly correlated with cardiothoracic ratio and right second arc diameter in CTEPH and PPH (Fig.6).

Discussion

The authors tried to identify characteristic patterns in chest roentgenograms to differentiate two representative diseases associated with severe chronic pulmonary hypertension (PH);chronic thromboembolic pulmonary hypertension (CTEPH)and primary pulmonary hypertension (PPH).CTEPH was associated with a pathognomonic avascular area,pleuritic scarring and right descending pul-monary arterial dilatation.PPH cases showed more prominent left 2nd arc protrusion and moderate right descending pulmonary arterial dilatation.By combining these ?ndings,the authors have selected new roentgenographic diagnostic patterns for chronic PH.The pattern of CTEPH is the existence of one of two ?ndings;an avascular area or right descending pulmonary artery diameter more than 20mm together with pleural abnormality.The diagnostic pattern of PPH is the existence of one of the following 2features;left 2nd arc protrusion more than 10mm or left 2nd arc protrusion of more than 5mm with right descending pulmonary artery diameter more than 20mm without pleural https://www.wendangku.net/doc/f83639701.html,ing these features,sensitivity and speci?city for CTEPH between the two precapillary PH diseases even with left heart disease was satisfactory,and for PPH speci?city was good and sensitivity fair .

Diseases associated with severe chronic PH are usually detected and diagnosed by history taking,physical examination and electrocardiography.Then the cause of PH will be sought and deter-mined after careful differential diagnosis.Fre-quently encountered diseases associated with PH are left heart disease,PPH,pulmonary parenchy-mal disease,Eisenmenger syndrome,CTEPH,

Table 3Roentgenographic diagnostic criteria.

Findings

CTEPH PPH LHD Avascular area or rtPA X 20mm and pleuritic scar

28/365/381/37Without pleural change,lt2ndArc X 10mm or lt2ndArc X 5mm and rtPA X 20mm

6/36

17/38

3/37

CTEPH:chronic thromboembolic pulmonary hypertension;LHD:left heart disease;lt2ndArc:degree of left second arc protrusion;PPH:primary pulmonary hypertension;rtPA:diameter of right descending pulmonary artery;Frequency in presence of each ?nding is

shown.

Figure 4Marked left second arc protrusion.Chest X-ray of 34-year-old woman.Mean pulmonary artery pressure was 75mm Hg.Protruded distance of left 2nd arc was 12mm.

Diagnosis of pulmonary hypertension by CXR

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hypoventilation syndrome,high output cardiac failure and other rare diseases.12Among the ?rst ?ve common etiologies,pulmonary parenchymal disease can be differentiated by chest roentogen-ography.Left heart disease and Eisenmenger syndrome can ordinarily be diagnosed by echocar-diography.The differential diagnosis of CTEPH and PPH is rather dif?cult and requires further studies such as perfusion lung scan,which is available only at certain institutions.If chest X-ray,which is performed in most clinics,can help differentiate the cause of severe chronic PH,it will make further scrutiny more smooth and ef?cient.

There have been many studies concerning chest X-ray ?ndings in patients with PH in general,13but very few reports have documented the roentgeno-graphic features of respective PH diseases or compared the ?ndings.Kanemoto et al.performed a pioneering study on the roentgenographic ?ndings in patients with PPH,claiming that main pulmonary artery protrusion was marked and had a rough correlation with pulmonary arterial pressure,and that CTR correlated with right atrial pressure and

right heart failure in PPH.4However ,in our study,left 2nd arc protrusion was prominent but did not correlate with pulmonary arterial pressure,and CTR did not correlate with right atrial pressure but with tricuspid regurgitation.The correlation coef?-cients between the main pulmonary artery dilata-tion and mean pulmonary arterial pressure and between CTR and right atrial pressure that Kane-moto et al.reported were 0.31and 0.37,barely signi?cant.Anderson et al.classi?ed PH patients according to pulmonary arterial dilatation and cardiomegaly,and revealed that patients with normal pulmonary arterial and cardiac con?gura-tion had the worst prognosis.9Our roentgeno-graphic patterns demonstrated high speci?city for diagnosis of PPH but low sensitivity,suggesting that the existence of main pulmonary artery protrusion and a large CTR signi?es severe PPH,but less marked protrusion or a normal CTR does not rule out PPH.CTR and right atrial pressure were correlated in patients with CTEPH in our study.The roentgenographic ?ndings found in CTEPH patients were studied in detail by Woodruff et al.6

Figure 5Relation of mean pulmonary arterial pressure with left 2nd arc protrusion and cardiothoracic ratio in three PH diseases.Mean pulmonary artery pressure and the other two roentgenographic variables were correlated by linear regression analysis.Left 2nd arc protrusion only re?ected the degree of pulmonary hypertension in left heart disease.Cardiothoracic ratio represented the severity of pulmonary hypertension in CTEPH and left heart disease.CTEPH:chronic thromboembolic pulmonary hypertension;CTR:cardiothoracic ratio;LHD:left heart disease;lt2ndArc:left second arc;mPA:mean pulmonary artery pressure;PPH:primary pulmonary hypertension.

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They reported that the signs frequently found in CTEPH were cardiomegaly(86%),oligemia(68%), right descending pulmonary artery enlargement (55%),effusion(23%)and pleural thickening(14%). We recognized similar?ndings with almost the same frequency.We showed that oligemia was very pathognomonic to differentiate CTEPH from any other PH diseases and that right descending pulmonary artery enlargement was prominent in CTEPH compared to PH due to left heart disease. Pleuritic change was more frequent in CTEPH than in PPH.By combining these?ndings,CTEPH can be diagnosed with good sensitivity and speci?city.In two representative precapillary PH diseases,CTR and right2nd arc width correlated with the degree of tricuspid regurgitation.In CTEPH in particular, CTR correlated with mean pulmonary arterial pressure and right atrial pressure,indicating that cardiomegaly well re?ects the severity of the disease.

Anderson et al.evaluated and compared the characteristic roentgenographic?ndings demon-strated in PPH and CTEPH and reported that patients with PPH had an enlarged pulmonary artery but those with CTEPH had pathognomonic oligemia9without pulmonary arterial dilatation. Their study patients had less severe PH and seemed to include patients with acute pulmonary embolism with less intimal thickening of the pulmonary artery,resulting in failure to demonstrate dilata-tion of the right descending pulmonary artery as an important?nding in CTEPH.Patients with PPH had greater left2nd arc protrusion owing to greater pulmonary hypertension,and those with CTEPH showed a wider branched pulmonary artery result-ing from thickened pulmonary intima.They also reported that some of the PPH patients with the worst prognosis had normal pulmonary artery diameter and CTR on chest roentogenography, indicating the lower sensitivity of roentgenographic diagnosis of PPH,consistent with our results. CTR and mPA were signi?cantly correlated in CTEPH and LHD,but not in PPH.This is partly because pulmonary artery pressures in patients with CTEPH and LHD were distributed over a wide range,but those in patients with PPH were

Figure6Relation of degree of tricuspid regurgitation with cardiothoracic ratio and right2nd arc width.Cardiothoracic ratio and right2nd arc width re?ected the degree of tricuspid regurgitation in CTEPH and PPH.CTEPH:chronic thromboembolic pulmonary hypertension;CTR:cardiothoracic ratio;LHD:left heart disease;rt2ndArc:right second arc;PPH:primary pulmonary hypertension.

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distributed within in a higher range,leading to the different statistical signi?cance among those dis-ease states.Essentially,CTR may be weakly correlated with the degree of PH regardless of the etiology.

CTR was well correlated with the degree of TR but not the mean right atrial pressure,although TR and right atrial pressure had a weak signi?cant correlation.Right atrial pressure is sometimes elevated in right heart failure but TR is not prominent when pulmonary hypertension is rapidly progressive.CTR is more in?uenced by chronic dilatation of right atrium and ventricle.

As a study limitation,the radiographic?ndings cannot lead to a de?nitive diagnosis,though they may be helpful for reaching a tentative diagnosis and to direct further diagnostic plans.When CTEPH is suspected from the radiographic?ndings,then CT scanning is preferred for the next diagnostic method,because CT is now the most accurate and non-invasive diagnostic tool.14

Conclusion

Characteristic chest roentgenographic features were sought to help differentiate two chronic pulmonary hypertension.Chronic thromboembolic pulmonary hypertension had a pathognomonic avascular area,pleuritic scarring and right des-cending pulmonary artery dilatation.Primary pul-monary hypertension had more prominent left2nd arc protrusion and moderate right descending pulmonary artery dilatation.By combining these ?ndings,new roentgenographic diagnostic patterns for chronic pulmonary hypertension were deter-mined.The former had good speci?city and fair sensitivity and the latter had satisfactory sensitiv-ity and speci?city among them and PH due to left heart disease.Cardiac dilatation associated with pulmonary hypertension re?ected the degree of tricuspid dilatation.References

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