Download Factors Associated With Pericardial Effusion in Acute Q Wave

477
Factors Associated With Pericardial Effusion
in Acute Q Wave Myocardial Infarction
Tetsuro Sugiura, MD, Toshiji Iwasaka, MD, Yasuo Takayama, MD, Masahide Matsutani, MD,
Tadashi Hasegawa, MD, Nobuyuki Takahashi, MD, and Mitsuo Inada, MD
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To elucidate the clinical characteristics associated with pericardial effusion in the early phase
of myocardial infarction, 330 patients with acute Q wave infarction were studied. According to
echocardiography, 83 patients had pericardial effusion on the third day of hospitalization, and
careful auscultation revealed that a pericardial rub was absent in 45 patients and was present
in 38 patients. Based on seven clinical variables, multivariate analysis was performed to
determine the important variables related to the occurrence of pericardial effusion with and
without pericardial rub. Pulmonary capillary wedge pressure and left ventricular segments with
advanced asynergy were the significant factors related to the occurrence of pericardial effusion
without a pericardial rub. The presence of ventricular aneurysmal motion, left ventricular
segments with advanced asynergy, and alveolar arterial oxygen diflerence were related to
pericardial effusion with a pericardial rub. Therefore, a hemodynamic factor was the major
mechanism associated with the increase in extravascular myocardial fluid and the consequent
occurrence of hydropericardia in the absence of a pericardial rub, whereas an increase in the
microvascular permeability in the myocardium with excessive fluid exudating through the
irritated epicardial surface was the mechanism related to pericardial effusion with a pericardial rub in the early phase of acute myocardial infarction. (Circulation 1990;81:477-481)
P ericardial effusion is one of the complications
occurring during the course of acute myocardial infarction, but there is marked variability
in its reported incidence, mechanisms, and clinical
significance.1-5 Echocardiography is the procedure of
choice for the detection of pericardial effusion, and
although pericardial effusion demonstrated by echocardiography may indicate fluid retention, this is not
diagnostic of pericardial injury. A pericardial rub is
not rare after acute myocardial infarction and has
been reported in patients with pericardial involvement near the infarct.1,6-9 Therefore, it is clinically
important to distinguish between irritant and hemodynamic factors contributing to the occurrence of
pericardial effusion in the early phase of acute myocardial infarction.
Because hydropericardia appears to result from an
increase in the production of myocardial interstitial
fluid or interference of fluid drainage,8 we hypothesized that hydrostatic pressure, osmotic pressure, and
myocardial vascular permeability affect the production
of pericardial fluid. In this investigation, we studied
From the Second Department of Internal Medicine, Kansai
Medical University, Osaka, Japan.
Address for reprints: Tetsuro Sugiura, MD, CCU, Kansai Medical University, 1 Fumizono-cho Moriguchi City, Osaka, Japan 570.
Received February 23, 1989; revision accepted September 28,
1989.
seven clinical factors that may affect the production of
pericardial fluid to elucidate the differences in the
clinical settings associated with the occurrence of
echocardiographically demonstrated pericardial effusion with and without a pericardial rub in patients
after their first acute Q wave infarction.
Methods
Patients
We studied 330 consecutive patients after their
first acute Q wave myocardial infarction (anterior
infarction, 203 patients; inferior infarction, 127
patients) who were admitted to the coronary care
unit within 24 hours from the onset of chest pain and
who survived the first 3 days after admission. It is a
routine procedure in our hospital to insert a SwanGanz catheter in patients with acute myocardial
infarction who were admitted within 24 hours from
the onset of chest pain. All the patients were examined by a physician, and written, informed consent
was obtained before the Swan-Ganz catheter insertion. None of the patients had chronic renal failure,
collagen disease, cardiac surgery within the previous
6 months, or metastatic disease. During this period, a
technically satisfactory echocardiogram could not be
obtained in 37 patients, and they were not included
in this study.
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Circulation Vol 81, No 2, February 1990
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Clinical Evaluation
The diagnosis of myocardial infarction was made
when the patients had an ST elevation with a new
Q wave (anterior infarction, two or more in V1 6;
inferior infarction, II, III, and aVF) in serial electrocardiograms and at least twice a normal elevation in
the level of serum creatine kinase with MB isoenzyme 5% or more. All patients were monitored
continuously in the coronary care unit, and all were
examined by careful auscultation at least twice daily.
Pericardial rub was considered as a to-and-fro
scratchy or grating noise heard in systole, middiastole, and presystole or in only one of these
phases, and the diagnosis of pericardial rub was
made after confirmation by at least two cardiologists.
Hemodynamic measurements including cardiac output, pulmonary capillary wedge pressure, and right
atrial pressure were determined by the Swan-Ganz
method. Pulmonary capillary wedge pressure and
right atrial pressure were determined at least once
every 4 hours, and cardiac output was determined
every 12 hours. The lowest cardiac output and highest pulmonary capillary wedge pressure and right
atrial pressure during 24 hours before the echocardiographic study were recorded. Total protein, albumin, and globulin levels were measured at the time of
admission and once daily for the first 3 days. Colloid
osmotic pressure was calculated according to the
Nitta-Staub's equation10: Colloid osmotic pressure =
a(2.8C+0. 18C2+0.012C3) +b(0.9C+0.12C2+0.004C3),
where a is albumin fraction, b is globulin fraction,
and C (g/dl) is total protein. Arterial blood was taken
from the radial or femoral arteries at the time of
admission with the patients breathing room air. The
alveolar arterial oxygen difference was calculated by
assuming a respiratory quotient equal to 0.8.
Echocardiography
Two-dimensional and M-mode echocardiography
were performed with an SSD 870 phased-array sector
scanner (Aloka, Tokyo). All classic views were
recorded on videotape for subsequent analysis by
observers who were unaware of the patients' clinical
data. The presence of pericardial effusion was
assessed on the third day of hospitalization with the
method described by Horowitz et al.11 An epicardialpericardial separation that persisted throughout the
cardiac cycle (D pattern) was considered diagnostic
of pericardial effusion.H1 To quantify the size of the
effusion, measurements were obtained at the level
of tips of the mitral valve as described by Weitzman
et al.12 Total effusion was graded as mild (<10 mm),
moderate (10-20 mm), or severe (>20 mm). A twodimensional echocardiogram was additionally used in
doubtful cases. Regional left ventricular wall motion
abnormalities were assessed by two-dimensional
echocardiography obtained on the third day of hospitalization. Analysis of the left ventricular wall was
performed with 11 segments obtained by long- and
short-axis images,13 and the number of segments with
advanced asynergy (akinesia or dyskinesia) was calculated. Functional left ventricular aneurysmal
motion was defined by two-dimensional echocardiography as an area of thinned myocardium that was
dyskinetic in systole with distinct diastolic deformity
and preserved adjacent wall motion.14
Coronary Arteriography
A coronary arteriogram was performed before each
patient was discharged from the hospital. Coronary
artery lesions with 70% or more reduction in diameter
were considered to be obstructive. Each patient was
classified as having one-, two-, or three-vessel disease.
The proximal left anterior descending lesion was
defined as a lesion before the first septal branch, and
the proximal right coronary artery lesion was defined
as a lesion before the acute marginal branch.
Statistical Analysis
Results are reported as the mean± SD. A Student's t test and a paired t test were used for
quantitative data, and x2 analysis was used for qualitative data. One-way layout analysis of variance and
Scheffd's multiple comparison were used to compare
the groups without pericardial effusion, with pericardial effusion but without pericardial rub, and with
pericardial effusion and pericardial rub. Discriminant analysis was performed to evaluate the important variables discriminating the two pericardial effusion groups with or without pericardial rub. The
categorical variable of aneurysmal motion was subdivided as either being absent or present. A p value
below 0.05 was considered significant.
Results
Incidence of Pericardial Effusion
Of the 330 patients with Q wave myocardial infarction, pericardial effusion was detected by echocardiography in 83 patients (57 men and 26 women; mean
age, 63+12 years) on the third day after admission and
was absent in 247 patients (180 men and 67 women;
mean age, 61±12 years). There were no significant
differences in the age and sex distribution between
patients with or without pericardial effusion. Among
the 83 patients with pericardial effusion, a pericardial
rub was absent in 45 patients (group 1) and was
present in 38 patients (group 2) during the first 3 days
after admission. Pericardial effusion was mild in 37
patients and was moderate in eight patients (18%) in
group 1, whereas 32 patients had mild and six
patients (16%) had moderate pericardial effusion in
group 2. There was no significant difference in the
incidence of moderate pericardial effusion between
the two groups. None of the patients had echocardiographic signs of severe pericardial effusion.
Clinical Characteristics of Pericardial Eff-usion
Without a Pericardial Rub
To determine the important variables associated
with the occurrence of pericardial effusion without a
Sugiura
et
al Pericardial Effusion in Myocardial Infarction
479
TABLE 1. Clinical Characteristics of Pericardial Effusion With and Without Pericardial Rub
Group 1
Group 2
No PE
(PE without PR)
(PE with PR)
(n=247)
(n=45)
(n=38)
F
p
Alveolar Pao2 D (Torr)
34+12
39±15
43+12
9.14
<0.001
CO (/min)
5.02±1.23
4.43±1.36
4.50±1.06
6.41
<0.01
PCW (mm Hg)
10±5
17±4
12±5
38.11
<0.001
RA(mm Hg)
4+3
6±3
6±4
6.49
<0.01
COP (mm Hg)
24+4
24±3
23±3
2.17
NS
Aneurysmal motion
Absent
220 (89%)
32 (71%)
22 (58%)
<0.001
X2=27.97
Present
27 (11%)
13 (29%)
16 (42%)
Asynergic segments
2.7±1.8
4.1±1.5
4.1±1.4
21.91
<0.001
PE, pericardial effusion; PR, pericardial rub; Alveolar Pao2 D, alveolar arterial oxygen difference; CO, cardiac output; PCW, pulmonary
capillary wedge pressure; RA, right atrial pressure; COP, colloid osmotic pressure; NS, not significant.
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pericardial rub (group 1), seven clinical variables
(alveolar arterial oxygen difference obtained at the
time of admission, cardiac output, pulmonary capillary wedge pressure, right atrial pressure, colloid
osmotic pressure, ventricular aneurysmal motion,
and the number of advanced asynergic segments
obtained on the third day after admission) were
compared with those without pericardial effusion and
were used in the discriminant analysis (Tables 1 and
2). As a result, pulmonary capillary wedge pressure
and advanced asynergic segments were found to be
the significant variables associated with the occurrence of pericardial effusion without a pericardial
rub. The probability of discriminance (1 -discriminant error) was 0.78.
Clinical Characteristics of Pericardial Effusion With a
Pericardial Rub
The seven clinical variables were also used in the
discriminant analysis to determine the important
variables contributing to the occurrence of pericardial effusion with a pericardial rub (group 2) (Tables
1 and 2). As a result, aneurysmal motion, advanced
asynergic segments, and alveolar arterial oxygen difference were identified as significant variables
related to the occurrence of pericardial effusion with
a pericardial rub. The probability of discriminance
(1-discriminant error) was 0.74.
Comparison of Selected Variables Between
Groups 1 and 2
When the four variables selected by the discriminant analysis were compared between the two
groups, group 1 had significantly higher pulmonary
capillary wedge pressure than group 2 (p<0.001).
There were no significant differences in alveolar
arterial oxygen difference, presence of aneurysmal
motion, and number of advanced asynergic segments
between the two groups. A coronary arteriogram was
obtained in 37 patients in group 1 and in 26 patients
in group 2. Thirteen patients in group 1 and 10
patients in group 2 had multivessel disease; the
difference was not significant. There were also no
significant differences between the two groups in the
rate of proximal left anterior descending and proximal right coronary artery lesions (54% and 58% in
groups 1 and 2, respectively).
Medication
Among the 83 patients with pericardial effusion, 27
patients received intravenous or intracoronary urokinase, whereas 76 patients with no evidence of pericar-
TABLE 2. Relation Between Seven Clinical Variables and Pericardial Effusion With and Without Pericardial Rub
Group 1
Group 2
(PE without PR)
PE with PR
Discriminant
F
Discriminant
F
coefficient
(adjusted)
coefficient
p
(adjusted)
p
Constant
-2.72
-0.92
Alveolar Pao2 D (Torr)
-0.01
0.26
NS
0.03
4.57
<0.05
CO (/min)
-0.23
2.12
NS
-0.10
0.34
NS
PCW (mm Hg)
0.30
44.25
<0.001
0.01
0.06
NS
RA (mm Hg)
-0.06
0.97
NS
0.07
1.05
NS
COP (mm Hg)
-0.03
0.24
NS
-0.09
2.78
NS
0.64
Aneurysmal motion
1.19
NS
2.19
14.35
<0.001
Asynergic segments
0.25
4.71
<0.05
0.30
6.55
<0.05
PE, pericardial effusion; PR, pericardial rub; Alveolar Pao2 D, alveolar arterial oxygen difference; CO, cardiac output; PCW, pulmonary
capillary wedge pressure; RA, right atrial pressure; COP, colloid osmotic pressure; NS, not significant.
480
Circulation Vol 81, No 2, February 1990
dial effusion received urokinase. There was no significant difference in the number of the patients who
received thrombolytic therapy between the group with
(33%) and the group without (31%) pericardial effusion. We routinely give heparin to all patients with
acute myocardial infarction in our coronary care unit.
Eleven patients with pericardial effusion and 44
patients without pericardial effusion were receiving
warfarin on the third day after admission, whereas 64
patients with pericardial effusion and 185 patients
without pericardial effusion were receiving an antiplatelet agent (aspirin). Similarly, no significant difference was seen between the two groups regarding the
use of anticoagulants and antiplatelet agent.
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Discussion
Pericardial effusion is a relatively common early
finding after acute myocardial infarction, but its
incidence is variable.1-5 Among the 83 patients with
pericardial effusion, a pericardial rub was absent in
45 patients (group 1) and was present in 38 patients
(group 2). Although pericardial rub is less often
detected than pericardial effusion, the 46% incidence
of pericardial rub in our patients with pericardial
effusion is less surprising. In this study, seven clinical
variables were examined to evaluate the relative
importance of each variable to the occurrence of
pericardial effusion with or without pericardial rub.
Two-dimensional echocardiography provides a
noninvasive means for visualization of abnormal left
ventricular wall motion, but this technique tends to
overestimate the infarct size.15-17 Therefore, in this
study, only advanced asynergy (akinesia and dyskinesia) was used to estimate the extent of myocardial
infarction. As a result, patients in group 1 had
significantly more segments with advanced asynergy
than patients without pericardial effusion, and
advanced asynergic segments were an important factor related to the occurrence of pericardial effusion
in the absence of pericardial rub, which indicates that
the patients in group 1 had more extensive myocardial damage.
Myocardial lymph drains to the subepicardium and
ultimately to the mediastinum and right heart
cavities.818 Thus, hydropericardia appears to result
from an increase in the production of myocardial
interstitial fluid or from interference of myocardial
venous and lymph drainage by elevated central
venous pressure.818 Fluid filtration across the microvascular system is governed by hydrostatic and
osmotic pressure generated in the microvessels and
interstitium. Because coronary flow drains into both
the right atrium and left ventricle in diastole, the rise
in right atrial and left ventricular diastolic pressure
would increase the hydrostatic pressure of the myocardial microvessels. Interestingly, Gee et al19 found
a significant increase in the extravascular myocardial
water after an increase in the left atrial pressure in
dogs when compared with a control series. Because
there was no significant difference in the colloid
osmotic pressure between the two groups, an
increase in hydrostatic pressure is considered to be
the factor associated with increased myocardial interstitial fluid volume. Therefore, although right atrial
pressure was not selected as a variable in this study,
our results from the multivariate analysis are in
keeping with previous findings suggesting that the
rise in the pulmonary capillary wedge pressure,
resulting from the hemodynamic change imposed on
the left ventricle from more extensive myocardial
damage, is associated with the occurrence of pericardial effusion in the absence of a pericardial rub.
Patients with pericardial effusion in the presence
of a pericardial rub (group 2) had a higher alveolar
arterial oxygen difference that was associated with
significantly more segments with advanced asynergy
and a higher incidence of aneurysmal motion than
those without pericardial effusion. Mechanisms considered as a cause of interstitial edema and congestion of the lung in acute myocardial infarction
include increased hydrostatic pressure or increased
pulmonary vascular permeability.19-21 The mechanism of increase in vascular permeability in acute
myocardial infarction is still unclear but Gee et a122
found that activation of formed elements in blood
may be involved in mediating vascular injury after
acute myocardial infarction. Furthermore, the
extravascular water content of the heart and lung
increased in the absence of an increase in left atrial
pressure after coronary artery ligation.'9 Because
pulmonary capillary wedge pressure in group 2 was
not critically elevated, the higher alveolar arterial
oxygen difference in group 2 patients than in those
patients without pericardial effusion suggests that an
increase in vascular permeability of heart and lung
existed in group 2 patients.
The development of infarct expansion or functional left ventricular aneurysmal motion is associated with a larger amount of myocardial necrosis and
anatomically transmural infarction.23,24 Transmural
myocardial infarction extends to the epicardial surface and is responsible for producing pericardial
inflammation in the infarct zone.8 Considering the
result of discriminant analysis, a possible mechanism
contributing to the occurrence of pericardial effusion
with a pericardial rub is increased extravascular
myocardial fluid due to increased vascular permeability associated with loss of interstitial fluid from the
myocardium to the pericardial space through the
damaged visceral pericardium as a result of higher
incidence of anatomically transmural infarction.
Limitations
Two limitations of our study should be addressed.
First, because of the transient nature of pericardial
rub, patients with irritative pericardial involvement
in whom a rub was missed could be included in the
noninflammatory group. However, the difference in
pulmonary capillary wedge pressure might have been
larger if 100% of the patients in groups 1 and 2 had
been correctly identified. Second, the small number
of patients in the groups with the conditions of
Sugiura et al Pericardial Effusion in Myocardial Infarction
interest, pericardial effusion without (45 patients) or
with (38 patients) a pericardial rub, might have led to
either the selection of variables by the discriminant
analysis that in reality are unimportant or might have
missed variables that are actually important. Nonetheless, an appraisal of our results in relation to
results from other studies and the consistency of
selected variables within our group of patients indicate that our conclusion would probably not be
altered by a larger group of patients.
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Conclusion
The present study demonstrates that patients in
group 1 had higher pulmonary capillary wedge pressures than patients in group 2, despite nearly identical coronary angiographic findings, extent of infarction, and disturbance of pulmonary gas exchange in
both groups. Thus, a hemodynamic mechanism is the
major factor contributing to the occurrence of pericardial effusion in the absence of a pericardial rub,
whereas an increase in capillary permeability and
excessive fluid exudating through the irritated epicardial surface are mechanisms associated with pericardial effusion with a pericardial rub in the early phase
of acute myocardial infarction.
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KEY WORDS * pericardium * echocardiography * hemodynamics
0 wave * infarctions
vascular permeability
Q
Factors associated with pericardial effusion in acute Q wave myocardial infarction.
T Sugiura, T Iwasaka, Y Takayama, M Matsutani, T Hasegawa, N Takahashi and M Inada
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Circulation. 1990;81:477-481
doi: 10.1161/01.CIR.81.2.477
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