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Echocardiographic diagnosis of aortic root dissection
ABSTRACTS
DIMINISHED LEFT PULMONARY BLOOD FLOW IN TRANSPOSITION OF THE GREAT ARTERIES. Alexander Muster, MD, FACC, Milton Paul, MD, FACC, Daniel Levin, MD, James Conway, MD, Edgar Newfeld, MD, Children's Memorial Hospital, Chicago, 111. In 5 infants with transposition of the great arteries (TGA), reduced left pulmonary blood flow was noted in angiograms at 3,5,18,22 and 32 months of age. Radionuclear scans showed a mean uptake for the group of 22% in the left and 78% in the right lung. The diagnosis was not suspected from the chest roentgenograms in any of the patients prior to angiography. Four infants had intact ventricular septum and mild subpulmonic stenosis and one had a large ventricular septal defect with severe stenosis. Qp/Qs was 1.0 or less in 4 infants. Atria1 septostomy in 3 and surgical septectomy in 1 infant was performed in early infancy but the aortic oxygen saturation (mean 53%) later was lower than expected considering the large atrial septal defect found af corrective surgery. Several mechanisms are considered for this unequal distribution of pulmonary blood flow: (1) In TGA an unusual angulation of the right and left pulmonary arteries at their junction with the main pulmonary artery may result in preferential flow to the right. (2) The Coanda effect generated in TGA by accelerated blood flow across the left ventricular outflow tract may favor blood streaming along the right wall of the pulmonary artery. The characteristic relationship of the pulmonary artery branch orifices accentuate this effect by preferentially splitting the stream towards the right lung. (3) In 2 infants, small left pulmonary vein orifices were found at the Mustard operation. These morphologic abnormalities may be either the cause or the result of long-standing diminished left pulmonary blood flow. We suggest that early corrective surgery be advised for these patients since repeat balloon septostomy or surgical septectomy did not improve the arterial oxygenation.
ECHOCARDIOGRAPHIC DISSECTION Navin
C.
Raymond University New
Nanda,
DIAGNOSIS
MD;
Kyung
J.
OF
Chung.
Gramiak, MD; Pravin of Rochester Medical
AORTIC
ROOT
MD;
M. Shah, MD, Center, Rochester,
York
Six patients
with
angiography, cardiography. to 21 mm.) except aortic
aortic
surgery
All patients of the anterior
one also wall,
root
dissection
or autopsy
showed
studied
showed increased wall of the aortic
a double
the separation
confirmed
were
contour
varying
by by echo-
width (16 root. All
of the posterior
from
10 to 13 mm.
(Normal mean aortic wall thickness 5. 7 mm. S. D. 1.2; aortic valve disease patients 6. 7 mm. S. D. 1. 5). 1n 4 patients slender aortic valve cusps were recorded moving
to the periphery
of the inner
and not extending to the outer lumen. useful in the absence of calcification which
may
produce
aortic root. Two tions in the width in the direction of dissection did not ference.
Other
confusing
multiple
lumen
in systole
This finding is of the aortic valve echoes
within
the
patients showed 8 to 20 mm. variaof the aortic image with slight change the transducer indicating that the uniformly involve the entire circum-
associated
seen in 3 patients. included cardial effusion and mitral
findings
on the echogram,
the demonstration of peridiastolic flutter suggestive
of aortic regurgitation. Demonstration of widening of the anterior and posterior walls of the aortic root with the normal motion of valve leaflets within the inner lumen appears to be a specific finding for aortic root involvement in dissecting aneurysm of the aorta.
150
January 1973
The American Journal of CARDIOLOGY
EXPERIMENTAL COARCTATION IN FETAL LAMBS Peter M. Olley, MD; Walter Zingg, MD, FACC; G. Kent, DVM; Murray Day, DVM. The Hospital for Sick Children, Toronto, Ontario, Canada. We have created preductal and postductal coarctation in fetal lambs at 65-70 days gestation (Term = 143 days) and compared the hemodynamic effects of pre- and post-ductal coarctation and the behaviour of the ductus arteriosus under these conditions. We operated on 73 fetuses, 22 survived to term, the remainder aborted. Survivors were delivered by cesarian section 24-48 hours before term. Cardiac output (CO), left and right ventricle pressures and the coarctation gradient were measured immediately after delivery in 20 animals (9 pre-ductal, 11 postductal). Dye dilution curves were used to detect ductal shunts. Cine aortograms were obtained to show the coarctation and collateral circulation. Finally the animals were sacrificed and formalin injected into the arterial tree, later a latex cast of the vessels was prepared, CO fell within the normal range for mature fetal lambs, mean coarctation gradient was significantly greater in the preductal group: 41 _f 17 mms.Hg. compared with 20 _+ 10 in the postductals. In most animals the ductus was closed or there was a small left to right shunt but in two animals with preductal coarctation, a large right to left shunt and systemic pressure in the pulmonary artery persisted. Injection studies showed extensive collaterals in both types but more marked in the postductal lesions. The model does not mimic spontaneous coarctation entirely, unlike human preductal lesions the ductus usually closes, suggesting that in clinical lesions ductal patency is due to an abnormal ductus rather than purely mechanical factors. The lesser gradient in the postductal group suggests that more severe lesions cause placental insufficiency incompatible with survival to term.
IDENTIFICATION OF THE PATIENTS AT HIGHEST RISK FOR SUDDEN DEATH WITHIN FIVE YEARS FOLLOWING THEIR FIRST MYOCARDIAL INFARCTION H.A. Oxman, MD, D.C. Connolly, MD, FACC, F.T. Nobrega, MD, J.L. Titus, MD. Mayo Clinic and Mayo Foundation, Rochester, Minnesota. To reduce the high mortality rate from ischemic heart disease (IHD), we must be able to identify the patients (PTS) at highest risk for sudden cardiac death (SCD). SCD is the most common mode of death for PTS with clinical IHD. As part of a broad community study of IHD among residents of Rochester, Minn., the identification of PTS at highest risk for SCD among the 579 residents who had their initial myocardial infarction (MI) between 1955-66 and survived it was undertaken. All had the opportunity of having a complete five year follow-up. The 579 PTS were divided into four groups according to status at five years following their first MI. Group Iliving (389), Group II-SCD (96), Group III-cardiac death, not sudden (47), Group IV-non cardiac death (47). The clinical characteristics of each group were analyzed and will be discussed in detail. Those dying of SCD were most likely to be males with hypertension, cardiomegaly, and angina following their first MI and most frequently had premature ventricular contractions on their one year follow-up electrocardiogram. Using the method of stepwise discriminant analysis, the following four variables were most important in predicting SCD at five years. Cardiomegaly; diastolic hypertension; history of congestive failure with first MI; and cigarette smoking. Using these four variables over 95% of those living and 80% of those with SCD were correctly classified at five years. It is felt that those individuals at highest risk for SCD following the first MI can be identified providing a basis for aggressive therapeutic intervention.
Volume 31
DIMINISHED LEFT PULMONARY BLOOD FLOW IN TRANSPOSITION OF THE GREAT ARTERIES. Alexander Muster, MD, FACC, Milton Paul, MD, FACC, Daniel Levin, MD, James Conway, MD, Edgar Newfeld, MD, Children's Memorial Hospital, Chicago, 111. In 5 infants with transposition of the great arteries (TGA), reduced left pulmonary blood flow was noted in angiograms at 3,5,18,22 and 32 months of age. Radionuclear scans showed a mean uptake for the group of 22% in the left and 78% in the right lung. The diagnosis was not suspected from the chest roentgenograms in any of the patients prior to angiography. Four infants had intact ventricular septum and mild subpulmonic stenosis and one had a large ventricular septal defect with severe stenosis. Qp/Qs was 1.0 or less in 4 infants. Atria1 septostomy in 3 and surgical septectomy in 1 infant was performed in early infancy but the aortic oxygen saturation (mean 53%) later was lower than expected considering the large atrial septal defect found af corrective surgery. Several mechanisms are considered for this unequal distribution of pulmonary blood flow: (1) In TGA an unusual angulation of the right and left pulmonary arteries at their junction with the main pulmonary artery may result in preferential flow to the right. (2) The Coanda effect generated in TGA by accelerated blood flow across the left ventricular outflow tract may favor blood streaming along the right wall of the pulmonary artery. The characteristic relationship of the pulmonary artery branch orifices accentuate this effect by preferentially splitting the stream towards the right lung. (3) In 2 infants, small left pulmonary vein orifices were found at the Mustard operation. These morphologic abnormalities may be either the cause or the result of long-standing diminished left pulmonary blood flow. We suggest that early corrective surgery be advised for these patients since repeat balloon septostomy or surgical septectomy did not improve the arterial oxygenation.
ECHOCARDIOGRAPHIC DISSECTION Navin
C.
Raymond University New
Nanda,
DIAGNOSIS
MD;
Kyung
J.
OF
Chung.
Gramiak, MD; Pravin of Rochester Medical
AORTIC
ROOT
MD;
M. Shah, MD, Center, Rochester,
York
Six patients
with
angiography, cardiography. to 21 mm.) except aortic
aortic
surgery
All patients of the anterior
one also wall,
root
dissection
or autopsy
showed
studied
showed increased wall of the aortic
a double
the separation
confirmed
were
contour
varying
by by echo-
width (16 root. All
of the posterior
from
10 to 13 mm.
(Normal mean aortic wall thickness 5. 7 mm. S. D. 1.2; aortic valve disease patients 6. 7 mm. S. D. 1. 5). 1n 4 patients slender aortic valve cusps were recorded moving
to the periphery
of the inner
and not extending to the outer lumen. useful in the absence of calcification which
may
produce
aortic root. Two tions in the width in the direction of dissection did not ference.
Other
confusing
multiple
lumen
in systole
This finding is of the aortic valve echoes
within
the
patients showed 8 to 20 mm. variaof the aortic image with slight change the transducer indicating that the uniformly involve the entire circum-
associated
seen in 3 patients. included cardial effusion and mitral
findings
on the echogram,
the demonstration of peridiastolic flutter suggestive
of aortic regurgitation. Demonstration of widening of the anterior and posterior walls of the aortic root with the normal motion of valve leaflets within the inner lumen appears to be a specific finding for aortic root involvement in dissecting aneurysm of the aorta.
150
January 1973
The American Journal of CARDIOLOGY
EXPERIMENTAL COARCTATION IN FETAL LAMBS Peter M. Olley, MD; Walter Zingg, MD, FACC; G. Kent, DVM; Murray Day, DVM. The Hospital for Sick Children, Toronto, Ontario, Canada. We have created preductal and postductal coarctation in fetal lambs at 65-70 days gestation (Term = 143 days) and compared the hemodynamic effects of pre- and post-ductal coarctation and the behaviour of the ductus arteriosus under these conditions. We operated on 73 fetuses, 22 survived to term, the remainder aborted. Survivors were delivered by cesarian section 24-48 hours before term. Cardiac output (CO), left and right ventricle pressures and the coarctation gradient were measured immediately after delivery in 20 animals (9 pre-ductal, 11 postductal). Dye dilution curves were used to detect ductal shunts. Cine aortograms were obtained to show the coarctation and collateral circulation. Finally the animals were sacrificed and formalin injected into the arterial tree, later a latex cast of the vessels was prepared, CO fell within the normal range for mature fetal lambs, mean coarctation gradient was significantly greater in the preductal group: 41 _f 17 mms.Hg. compared with 20 _+ 10 in the postductals. In most animals the ductus was closed or there was a small left to right shunt but in two animals with preductal coarctation, a large right to left shunt and systemic pressure in the pulmonary artery persisted. Injection studies showed extensive collaterals in both types but more marked in the postductal lesions. The model does not mimic spontaneous coarctation entirely, unlike human preductal lesions the ductus usually closes, suggesting that in clinical lesions ductal patency is due to an abnormal ductus rather than purely mechanical factors. The lesser gradient in the postductal group suggests that more severe lesions cause placental insufficiency incompatible with survival to term.
IDENTIFICATION OF THE PATIENTS AT HIGHEST RISK FOR SUDDEN DEATH WITHIN FIVE YEARS FOLLOWING THEIR FIRST MYOCARDIAL INFARCTION H.A. Oxman, MD, D.C. Connolly, MD, FACC, F.T. Nobrega, MD, J.L. Titus, MD. Mayo Clinic and Mayo Foundation, Rochester, Minnesota. To reduce the high mortality rate from ischemic heart disease (IHD), we must be able to identify the patients (PTS) at highest risk for sudden cardiac death (SCD). SCD is the most common mode of death for PTS with clinical IHD. As part of a broad community study of IHD among residents of Rochester, Minn., the identification of PTS at highest risk for SCD among the 579 residents who had their initial myocardial infarction (MI) between 1955-66 and survived it was undertaken. All had the opportunity of having a complete five year follow-up. The 579 PTS were divided into four groups according to status at five years following their first MI. Group Iliving (389), Group II-SCD (96), Group III-cardiac death, not sudden (47), Group IV-non cardiac death (47). The clinical characteristics of each group were analyzed and will be discussed in detail. Those dying of SCD were most likely to be males with hypertension, cardiomegaly, and angina following their first MI and most frequently had premature ventricular contractions on their one year follow-up electrocardiogram. Using the method of stepwise discriminant analysis, the following four variables were most important in predicting SCD at five years. Cardiomegaly; diastolic hypertension; history of congestive failure with first MI; and cigarette smoking. Using these four variables over 95% of those living and 80% of those with SCD were correctly classified at five years. It is felt that those individuals at highest risk for SCD following the first MI can be identified providing a basis for aggressive therapeutic intervention.
Volume 31