J. ROSENWEIG AND S. CHATTERJEE 
133 
mm.Hg 
20. 
10. 
LEFT ATIIIAI PRESSURE 
o. 
C/min. 
100, 
SO. 
60. 
45. 
30. 
IS. 
(hours) 
CORONARY FLOW 
(hours) 
[iactate] 
l./bnin. 
3jO. 
2J0. 
IjO. 
O. 
CARDIAC OUTPUT 
mm.Hg 
ISO. 
120. 
60. 
O. 
AORTIC PRiSSURi 
Dyn«»/em./ioc."5 
5000. 
PERIPHERAL VASCULAR RESISTANCE 
(hours) 
LEFT VENTRICULAR WORK 
(hours) 
iiigiii^X) 
200. 
I60. 
(hours) 
ARTERIAL OXTOEN TENSION 
120. 
(hours) 
(hours) 
Figure 14. — Graphs illustrating the effects on hemodynamics and myocardial metabolism ob- 
served in animals treated by arterio-arterial counterpulsation. Mean finding in ten dogs. 
sation rapidly restored and effectively main- 
tained peripheral circulation in cardiogenic 
shock until the heart recovered from its acute 
ischemic injury. Improvement in myocardial 
function was undoubtedly related to the in- 
creased total and collateral coronary flow as a 
result of diastolic augmentation and increased 
cardiac output. The method has obvious ad- 
vantages over arterio-arterial counterpulsation 
for it avoids extracorporeal circulation. Balloon 
rupture and air embolism were not encountered. 
Recent improvement in design fabrication 
should minimize this risk. 
Pulsatile veno-arterial bypass with oxygena- 
tion, like arterio-arterial counterpulsation, has 
the disadvantage of extracorporeal circulation. 
However, the primary requirements of any cir- 
culatory assistance are fulfilled by the unique 
characteristics of its pulse pressure generator. 
It permits the arterial bypass with oxygenation 
(pumps arterialized blood), incorporates syn- 
chronized pulsatile flow and diastolic augmen- 
tation (counterpulsation), maintains peripheral 
circulation, restores normal organ function and 
is gentle to blood over prolonged periods with- 
out evidence of embolization. The latter is prob- 
ably related to the absence of an outflow valve 
eliminating a major impediment to flow and a 
site of turbulence. Use of more nonthrombo- 
genic materials could eliminate the need for 
anticoagulation and use of a membrane oxy- 
genator could make it safe for extended periods 
of assistance. The experiments clearly indicated 
that this method of support was capable of 
maintaining circulation until the heart recov- 
ered from its acute ischemic injury. As with the 
other methods, the improved myocardial func- 
tion was no doubt related to increased coronary 
flow and to enhanced collateral circulation, as a 
result of elevated mean aortic pressure, partic- 
ularly increased diastolic pressure. Although 
diastolic augmentation was not as marked as 
observed with arterio-arterial counterpulsation, 
it was nevertheless effective. At low flow states, 
such as cardiogenic shock, coronary artery 
pressure in the ischemic bed can approach 
