Distribution of pleural effusion in congestive heart failure: what is atypical?

Objectives: This study was performed to determine the distribution of pleural effusion between the right and left hemithorax in patients with uncomplicated congestive heart failure, and to determine whether left-sided pleural effusion actually constitutes an atypical distribution in congestive heart failure.

Methods: The study group consisted of 120 consecutive patients with both clinical and radiographic evidence of uncomplicated congestive heart failure, and whose chest radiographs at the time of presentation also showed evidence of pleural effusion. The presence or absence of pleural effusion in the right and left hemithorax was recorded for each case, as was the size of each pleural effusion, and the distribution of pleural effusion in these 120 patients was entered into a 2 X 2 table and analyzed by [chi square] analysis.

Results: There were 207 total pleural effusions, with 105 on the right and 102 on the left. Isolated right-sided pleural effusions occurred in 18 patients, there were bilateral pleural effusions larger on the right than the left in 25, there were bilateral pleural effusions of roughly equal size on each side in 36, there were bilateral pleural effusions larger on the left side than the right in 26, and there were isolated left-sided pleural effusions in 15. The difference was not statistically significant ([chi square] = 0.316; P [less than or equal to] 1.0).

Conclusions: Left-sided pleural effusion is not an atypical finding in congestive heart failure and is not, in and of itself, an indication for further clinical or imaging evaluation.

Key Words: congestive heart failure, pleural effusion

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It is well known and universally accepted that in patients with congestive heart failure (CHF), an isolated left-sided pleural effusion or the presence of bilateral pleural effusion that is larger on the left side than the right is not compatible with uncomplicated CHF, and a diagnosis other than CHF, most notably pulmonary infarction, should be sought. (1-13) In particular, an isolated left pleural effusion is considered to be distinctly unusual in uncomplicated CHF. (1-13) In addition to pulmonary infarction, pericardial disease, prior coronary artery bypass graft surgery, and superimposed left-sided pneumonia or neoplasm have also been suggested as possible causes of left-sided pleural effusion in patients with CHF. (1,8-11) In a patient with CHF, the presence of an isolated left pleural effusion or bilateral pleural effusion that is larger on the left side than the right can result in an extensive workup that may include thoracentesis one or more times, ventilation-perfusion scintigraphy, and/or spiral computed tomography in an attempt to determine the cause of the left-sided pleural effusion. This is not without risk or expense.

Over the last 25 years, it has been my personal impression that left-sided pleural effusion is not uncommon in uncomplicated CHF, and that workups to determine the cause of the left-sided pleural effusion in patients with CHF often reveal no cause other than the CHF. Because of this, I undertook a study to determine what the distribution of pleural effusion was in patients with uncomplicated CHF and to see if left-sided pleural effusion actually constitutes an atypical distribution of pleural effusion in CHF.

Materials and Methods

The study group consisted of 120 consecutive males, ranging in age from 44 to 92 years (average, 71 years), who presented to the hospital with both clinical and radiographic evidence of uncomplicated CHF, and whose upright posteroanterior (PA) and lateral chest radiographs at the time of presentation demonstrated radiographic evidence of pleural effusion.

Clinical signs and symptoms of cardiac disease in these 120 patients included characteristic angina pectoris in 21 (17.5%), shortness of breath in 92 (76.6%), dyspnea on exertion in 34 (28.3%), orthopnea in 34 (28.3%), paroxysmal nocturnal dyspnea in 21 (17.5%), cough productive of pink frothy sputum in 2 (1.6%), rales in 47 (39.2%), systolic murmurs in 14 (11.6%), S3 and S4 gallop in 1 (0.8%), jugular venous distention in 32 (26.6%), lower extremity edema in 79 (65.8%), ascites in 5 (4.2%), and anasarca in 2 (1.6%). Six (5%) of the 120 patients were shown by both electrocardiography and enzyme changes to have acute myocardial infarction at the time of presentation. Fifty-four (45%) of the 120 patients had prior or current arrhythmias. This included atrial fibrillation in 43 (35.8%), atrial flutter in 10 (8.3%), and ventricular tachycardia in 1 (0.8%). Twenty-one (17.5%) of the patients had tachycardia at presentation; this was due to atrial fibrillation with a rapid ventricular response in 10 (8.3%), atrial flutter in 10 (8.3%), and ventricular tachycardia in 1 (0.8%). Forty-seven (39.2%) of the 120 patients had undergone prior coronary artery bypass graft surgery. Fifty-seven (47.5%) of the 120 patients had diabetes mellitus; 101 (84.2%) had either current or prior documented hypertension, and 69 (57.5%) had dyslipidemia. To be relatively certain that the study group represented patients with uncomplicated CHF, patients with documented pulmonary embolism, pneumonia, or neoplasm were not included in the study.

Ischemic heart disease was present in 106 (88.3%) of the 120 patients. Documentation of this included angiographic evidence of hemodynamically significant coronary arterial stenosis in 80 cases, prior documented myocardial infarction in 60, current acute myocardial infarction in 6, characteristic angina pectoris in 21, and a recent positive stress test in 3.

Dilated cardiomyopathy was present in 4 (3.3%) of the 120 patients. This was alcohol related in one case and idiopathic in three.

Aortic stenosis was present in 15 (12.5%) of the 120 patients. Based on the aortic valve area calculated at echocardiography (ECHO), this was classified as mild in 3 (2.5%) cases, moderate in 2 (1.6%), and severe in 10 (8.3%). Moderate aortic insufficiency was documented by ECHO in 9 (7.5%) of the 120 patients, and severe aortic insufficiency was present in 1 (0.8%).

Mitral stenosis was present in 2 (1.6%) of the 120 patients. Based on the peak valve gradient calculated at ECHO, this was characterized as being moderate in one (0.8%) case and mild in one (0.8%) case. Moderate mitral regurgitation was documented by ECHO in 41 (34.2%) of the 120 patients, and severe mitral regurgitation with reversal of blood flow in the pulmonary veins was present in 13 (10.8%).

Moderate tricuspid regurgitation was documented by ECHO in 32 (26.7%) of the 120 patients, and severe tricuspid regurgitation was present in 12 (10%). The right ventricular systolic pressure was elevated in 74 (61.7%) of the 120 patients.

Abnormalities of left ventricular wall motion (hypokinesis, akinesis, and/or dyskinesis) were documented by ECHO in 97 (80.8%) of the 120 patients. True aneurysms of the left ventricular apex were present in 4 of these cases. The left ventricular ejection fraction was decreased, ranging from 10 to 45%, in 88 (73.3%) of the 120 patients. The left ventricular ejection fraction was normal, ranging from 50 to 70%, in the remaining 32 (26.7%). Small pericardial effusions were noted by ECHO in 25 (20.8%) of the 120 patients.

All 120 (100%) patients had cardiomegaly on their PA and lateral chest radiographs at the time of presentation. The following radiographic signs of left-sided CHF were also noted on these PA and lateral chest radiographs. There was cephalization of pulmonary blood flow indicating pulmonary venous hypertension in all 120 (100%) cases. Interstitial pulmonary edema was present in 93 (77.5%) of the 120 cases. This was manifested by vascular indistinctness or haze in 76, thickening of the interlobular septa in 50, bronchial cuffing in 18, and diffuse reticulation in 9. Alveolar pulmonary edema was present in 11 (9.2%) of the 120 cases.

Based on the combination of radiographic and clinical findings, left-sided heart failure was thought to be present in all 120 (100%) cases. There was systolic dysfunction of the left ventricle with a reduced ejection fraction (45% or less) in 88 (73.3%) of the 120 patients. This was due to ischemic heart disease in 76 cases, severe aortic stenosis in 3, combined ischemic heart disease and severe aortic stenosis in 3, cardiomyopathy in 4, and severe uncontrolled hypertension in 2. Systolic dysfunction of the left ventricle was complicated further by severe mitral regurgitation with reversal of blood flow in the pulmonary veins in 10 cases, moderate mitral regurgitation in 32, severe aortic insufficiency in 1, moderate aortic insufficiency in 7, mild aortic stenosis in 2, moderate mitral stenosis in 1, mild mitral stenosis in 1, atrial flutter in 8, atrial fibrillation with a rapid ventricular response in 7, and ventricular tachycardia in 1.

In 28 (23.3%) of the 120 cases, diastolic dysfunction of the left ventricle was considered to be the main cause of left-sided heart failure. Diastolic dysfunction of the left ventricle was related to concentric left ventricular hypertrophy and/or decreased left ventricular diastolic filling times. Twenty-five of these 28 patients had hypertension, 4 had severe aortic stenosis, 2 had moderate aortic stenosis, 3 had atrial fibrillation with a rapid ventricular response, and 2 had atrial flutter. Diastolic dysfunction of the left ventricle was complicated further by ischemic heart disease in 23 cases, moderate mitral regurgitation in 8, and moderate aortic insufficiency in 1.

Left-sided heart failure was thought to be related predominantly to mitral valvular regurgitation in the remaining four (3.3%) patients. Three of these patients had severe mitral regurgitation with reversal of blood flow in the pulmonary veins and one had moderate mitral regurgitation. This was complicated by ischemic heart disease in all four cases, mild aortic stenosis in one, and moderate aortic insufficiency in one.

In addition, there was clinical and/or ECHO evidence of right-sided cardiac dysfunction in 106 (88.3%) of the 120 patients. Clinical signs of right-sided cardiac failure were present in 89 (74.2%) patients and included jugular venous distention in 32, lower extremity edema in 79, ascites in 5, and anasarca in 2, ECHO evidence of right-sided cardiac abnormality was present in 79 (65.8%) of the 120 patients and included moderate or severe tricuspid regurgitation in 44 and elevated right ventricular systolic pressure in 74.

The following signs of pleural effusion were evaluated on each patient's PA and lateral chest radiograph obtained at the time of presentation: blunting of the posterior and lateral costophrenic angles; the meniscus sign; manifestations of subpulmonic collection of pleural effusion including increased separation of aerated right lung and subdiaphragmatic fat on the right compared with prior chest radiographs, increased separation of aerated left lung and the gastric air bubble on the left compared with prior chest radiographs, and flattening or lateral shift of the "apparent" apex of the right or left hemidiaphragm (pseudodiaphragm) compared with prior chest radiographs; and obscuration of pulmonary vessels below the level of the upper margin of the pleural effusion or right or left pseudodiaphragm. (14-18) The presence or absence of pleural effusion in the right and left hemithorax was recorded for each case.

The size of pleural effusion was roughly quantified as follows. If minimal detectable blunting of the posterior and/or lateral costophrenic angle was evident on the PA and lateral chest radiograph, the quantity of pleural effusion was classified as small. This is reported to correlate with pleural effusions in the range of 25 to 525 mL. (17,19-21) Effusions were classified as moderate in size if the effusion occupied the lower part of the hemithorax but did not extend above the fourth rib anteriorly on the PA view. This correlates with pleural effusions larger than 525 mL. (17,19-21) Large effusions extended above the level of the fourth anterior rib on the PA view. (19-21)

The distribution of pleural effusion was recorded in each case as falling into one of the following five categories: right-sided only; bilateral but larger on the right side than the left; bilateral and of roughly equal size on each side; bilateral but larger on the left side than the right; and left-sided only. When there were bilateral pleural effusions, the following criteria were used to determine whether or not the effusions were of the same size. Since the posterior costophrenic angle is lower in position in the hemithorax than the lateral costophrenic angle, small pleural effusions typically cause blunting of the posterior costophrenic angle on the lateral chest radiograph before they cause blunting of the lateral costophrenic angle on the PA chest radiograph. (15) Small bilateral pleural effusions were classified as being of the same size if there was either minimal blunting of both the right and left posterior costophrenic angles, or if there was minimal blunting of both the right and left posterior and lateral costophrenic angles. Small pleural effusions resulting in blunting of both the posterior and lateral costophrenic angles on one side were said to be larger than small pleural effusions that caused blunting of the posterior costophrenic angle only on the other side. Moderate and large bilateral pleural effusions were said to be of the same size if the position of the highest point of the meniscus of fluid along the right lateral chest wall was at the same level as the highest point of the meniscus of fluid along the left lateral chest wall, or if the two were separated by a centimeter or less. Moderate or large pleural effusions on one side were said to be larger than moderate or large pleural effusions on the contralateral side if the position of the highest point of the meniscus of fluid along the lateral chest wall on one side was higher than that on the contralateral side by more than one centimeter. The patients' medical records were also reviewed to see if thoracentesis was performed in any of these cases.

The distribution of pleural effusion between the right and left hemithorax in the 120 patients with congestive heart failure was entered into a 2 X 2 table and was analyzed by [chi square] analysis. The distribution of pleural effusion in the 25 patients with pericardial effusion and the 47 patients with prior coronary artery bypass graft surgery was also entered into 2 X 2 tables and analyzed by [chi square] analysis.

Results

There were 207 total pleural effusions among the 120 patients; 105 occurred on the right side and 102 occurred on the left. The radiographic signs of pleural effusion on the right included a blunted posterior costophrenic angle with a meniscus sign in 98 (93.3%) of the 105 right-sided pleural effusions, a blunted lateral costophrenic angle with a meniscus sign in 85 (80.9%), increased separation of aerated right lung and right-sided subdiaphragmatic fat compared with prior chest radiographs in 2 (1.9%), flattening and/or lateral shift of the apex of the right pseudodiaphragm compared with prior chest radiographs in 32 (30.5%), and obscuration of pulmonary vessels below the level of the upper margin of the pleural effusion or right pseudodiaphragm in 58 (55.2%). Fifty-seven (54.3%) of the 105 right-sided pleural effusions were classified as small, 46 (43.8%) were moderate in size, and 2 (1.9%) were large. The radiographic signs of pleural effusion on the left included a blunted posterior costophrenic angle with a meniscus sign in 97 (95.1%) of the 102 left-sided pleural effusions, a blunted lateral costophrenic angle with a meniscus sign in 85 (83.3%), increased separation of aerated left lung and the gastric air bubble compared with prior chest radiographs in 64 (62.7%), flattening and/or lateral shift of the apex of the left pseudodiaphragm compared with prior chest radiographs in 17 (16.7%), and obscuration of pulmonary vessels below the level of the upper margin of the pleural effusion or left pseudodiaphragm in 69 (67.6%). Fortynine (48%) of the 102 left-sided pleural effusions were classified as small, 50 (49%) were moderate in size, and 3 (2.9%) were large.

The distribution of pleural effusion between the right and left hemithorax was as follows: isolated right-sided pleural effusions occurred in 18 (15%) of the 120 patients; there were bilateral pleural effusions that were larger on the right side than the left in 25 (20.8%); there were bilateral pleural effusions that were of roughly equal size on each side in 36 (30%); there were bilateral pleural effusions that were larger on the left side than the right in 26 (21.7%); and there were isolated left-sided pleural effusions in 15 (12.5%) (Table). There was no statistically significant difference in the distribution of pleural effusion between the right and left hemithorax in these 120 patients ([chi square] = 0.316; P [less than or equal to] 1.0).

In the 25 cases with small pericardial effusions, there were isolated unilateral right pleural effusions in three, bilateral pleural effusions larger on the right than the left in nine, bilateral pleural effusions of roughly equal size in six, and bilateral pleural effusions larger on the left than the right in seven. None had isolated unilateral left pleural effusion. Overall, there was right pleural effusion in all 25 cases and left pleural effusion in 22. The difference was not statistically significant ([chi square] = 3.191; P [less than or equal to] 0.10).

In the 47 cases with prior coronary artery bypass graft surgery, there were isolated unilateral right pleural effusions in 8, bilateral pleural effusions larger on the right than the left in 10, bilateral pleural effusions of roughly equal size in 11, bilateral pleural effusions larger on the left than the right in 12, and isolated unilateral left pleural effusions in 6. Overall, there was right pleural effusion in 41 cases and left pleural effusion in 39. The difference in the distribution of pleural effusion in these patients was not statistically significant ([chi square] = 0.335; P [less than or equal to] 1.0).

A review of the patients' medical records showed that thoracentesis was performed in seven cases. This included one large and two small right pleural effusions and one moderate and three large left pleural effusions. All seven were transudates.

Discussion

Over the last 60 years, it has been published widely that there is a marked predominance of right-sided pleural effusion in patients with CHF. (1-13) Although there is no known explanation for this, it is generally accepted that the presence of an isolated left-sided pleural effusion or bilateral pleural effusion that is larger on the left side than the right is not compatible with uncomplicated CHF, and a cause for the left-sided pleural effusion other than CHF should be sought. (1-13) Pulmonary infarction is usually mentioned as the most likely cause of isolated or predominantly left-sided pleural effusions in patients with CHF, although superimposed left-sided pneumonia or malignancy, pericardial disease, and prior coronary artery bypass graft surgery also have been mentioned as possible causes. (1-13)

Although some of the evidence concerning the predominance of right-sided pleural effusion in patients with CHF is anecdotal, (1,9) there are reported series of patients in the older literature that are widely believed to have documented the right-sided predominance of pleural effusion in patients with CHF and to have confirmed that pulmonary infarction is a significant cause of isolated or predominantly left-sided pleural effusion in patients with CHF. In particular, three autopsy series of patients reported between 1946 and 1957 are often cited as having proven this. However, there are problems with these reports and the conclusions that are often drawn from them.

Although White et al (11) did not exclude small pleural effusions from their study, McPeak and Levine (12) and Race et al (13) excluded all pleural effusions less than 300 mL and 250 mL, respectively. Since these smaller effusions were not recorded, the true incidence and distribution of pleural effusion in their cases is unknown.

Furthermore, none of the three performed a statistical analysis of their data. As a result, the "significance" of the findings and conclusions can be questioned easily. McPeak and Levine, (12) in 1946, reported 110 autopsy cases with CHF and pleural effusion and found isolated right-sided pleural effusions in 6, bilateral pleural effusions in 99, and isolated left-sided pleural effusions in 5. White et al, (11) in 1947, reported 100 autopsy cases with CHF and pleural effusion and found isolated right-sided pleural effusions in 15, bilateral pleural effusions in 72, and isolated left-sided pleural effusions in 11. Race et al, (13) in 1957, reported 290 autopsy cases with CHF and pleural effusion and found isolated right-sided pleural effusions in 24, bilateral pleural effusions in 255, and isolated left-sided pleural effusions in 11. By combining the three series, the distribution of pleural effusion can be evaluated in 500 autopsy cases of CHF. In these 500 cases, 45 had isolated right-sided pleural effusions, 426 had bilateral pleural effusions, and 29 had isolated left-sided pleural effusions. Although there are 16 more right-sided pleural effusions than left-sided pleural effusions, [chi square] analysis shows that the difference is not significant ([chi square] = 3.735; P [less than or equal to] 0.10).

Pulmonary infarcts were found at autopsy in 126 of these 500 cases. (11-13) Fourteen of these 126 patients had isolated right-sided pleural effusions, 103 had bilateral pleural effusions, and only 9 had isolated left-sided pleural effusions. It is interesting to note that there were actually more right-sided pleural effusions than left-sided pleural effusions in these cases. [chi square] analysis shows that the difference in distribution of pleural effusion between the right and left hemithorax in these 126 cases with pulmonary infarcts and CHF is not significant ([chi square] = 1.196; P [less than or equal to] 1.0).

Fifty-nine of the patients reported by Race et al (13) had pneumonia at autopsy. Four had isolated right-sided pleural effusions, 54 had bilateral pleural effusions, and only 1 had an isolated left-sided pleural effusion. The difference in distribution of pleural effusion between the right and left hemithorax in these 59 cases is not significant, either ([chi square] = 1.879; P [less than or equal to] 0.20).

Finally, it is reasonable to believe that the incidence of pulmonary infarction and pneumonia at autopsy in patients with CHF may not accurately reflect the incidence of pulmonary infarction and pneumonia in living patients with CHF at the time they initially present to medical attention.

In the current study of 120 consecutive patients with both clinical and radiographic evidence of CHF, who also had radiographic evidence of pleural effusion at the time of presentation, there was no difference in the distribution of pleural effusion between the right and left hemithorax. To be relatively certain that these cases represented cases of uncomplicated CHF, patients with clinical or radiographic evidence of pulmonary embolism, pneumonia, or neoplasm were not included in the study. Overall, there were 207 pleural effusions among the 120 patients; 105 occurred on the right and 102 occurred on the left. There were isolated right-sided pleural effusions in 18 of the 120 patients, bilateral pleural effusions that were larger on the right side than the left in 25, bilateral pleural effusions that were of roughly equal size on each side in 36, bilateral pleural effusions that were larger on the left side than the right in 26, and isolated left-sided pleural effusions in 15 (Table). The difference was not statistically significant ([chi square] = 0.316; P [less than or equal to] 1.0). Similarly, there was no significant difference in the distribution of pleural effusion in the patients who also had pericardial effusion or those who had had prior coronary artery bypass graft surgery.

The results of the current study are supported by several other reports in the literature. In 1983, Peterman and Brothers (22) reported the distribution of pleural effusion in 54 patients with CHF and transudative pleural effusions on thoracentesis who also had chest radiographs available for review. Two of these 54 patients had isolated right-sided pleural effusions, 16 had bilateral pleural effusions larger on the right than the left, 19 had bilateral pleural effusions of equal size, 14 had bilateral pleural effusions larger on the left than the right, and 3 had isolated left-sided pleural effusions. Thus, 51 of their 54 patients had right-sided pleural effusions and 52 had left-sided pleural effusions. They did not perform a statistical analysis of their data; however, they concluded that the right-sided predominance of pleural effusion in patients with CHF was not clinically significant. Retrospective [chi square] analysis of their data shows that the difference is not statistically significant ([chi square] = 0.209; P [less than or equal to] 1.0). The results are very similar to those of the current study.

In addition, Kalomenidis et al, (23) in a study of 27 patients with bilateral pleural effusions of various causes including CHF, who had undergone bilateral thoracentesis, found no significant difference in the chemical or cellular analysis of the right-sided and left-sided pleural effusions in their cases, and specifically no difference between the right and left side in any given case. There were no cases in which there was a transudate on one side and an exudate on the other. (23) They concluded that patients with bilateral pleural effusion do not need bilateral thoracentesis unless there is a compelling clinical reason. (23) Although the findings in this paper are not applicable to patients with CHF and unilateral pleural effusion, they do suggest that there would be no significant difference in bilateral pleural effusions in patients with CHF regardless of which side the larger pleural effusion was on.

Conclusion

In patients with uncomplicated CHF, there is no significant difference in the distribution of pleural effusion between the right and left hemithorax. A retrospective review and statistical analysis of some of the older literature suggests that the well-known association between left-sided pleural effusion and pulmonary infarction in patients with CHF is also not significant. Left-sided pleural effusion is not an atypical finding in CHF and is not, in and of itself, an indication for further clinical or imaging workup to find a cause other than CHF. In patients with CHF, the decision to workup a left pleural effusion, or a right pleural effusion for that matter, for a cause other than CHF should be based on clinical findings such as pleuritic chest pain, severe hypoxemia, hemoptysis, documented deep venous thrombosis, unexplained weight loss, fever, elevated white blood cell count, or chest radiographic evidence of a mass or infiltrate, rather than on the location of the pleural fluid alone. As always, a pleural effusion in a patient with no clinical or radiographic evidence of CHF requires diagnostic evaluation.

But yet I am firmly persuaded that a great deal of consciousness, every
sort of consciousness, in fact, is a disease.
--Fyodor Dostoevsky, Notes From The Underground

Table. Distribution of pleural effusion in 120 patients with
uncomplicated congestive heart failure

Right pleural effusion only  18 (15%)
Bilateral effusion R > L     25 (20.8%)
Bilateral effusion R = L     36 (30%)
Bilateral effusion L > R     26 (21.7%)
Left pleural effusion only   15 (12.5%)

Difference between the right and left side is not significant
([chi square] = 0.316; P [less than or equal to] 1).

Accepted October 5, 2004.

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RELATED ARTICLE: Key Points

* A review of the chest radiographs of 120 consecutive patients with clinical and radiographic evidence of uncomplicated congestive heart failure, who also had radiographic evidence of pleural effusion, revealed a total of 207 pleural effusions, with 105 right-sided and 102 left-sided pleural effusions.

* The difference in the distribution of pleural effusion between the right and left hemithorax was not statistically significant ([chi square] = 0.316; P [less than or equal to] 1.0).

* Left-sided pleural effusion is not an atypical finding in congestive heart failure and is not, in and of itself, an indication for further clinical or imaging evaluation.

John H. Woodring, MD

From the Radiology Service, Department of Veterans Affairs Medical Center, Lexington, KY.

Reprint requests to Dr. John H. Woodring, Radiology Service (114-CDD), Department of Veterans Affairs Medical Center, 1101 Veterans Drive, Lexington, KY 40502-2236. Email: [e-mail]