Distal coronary artery perfusion during percutaneous transluminal coronary angioplasty

October,

Cassling

et al.

American

37. Marboe CC, Knowles DM, Weiss MB, Ursell PC, Fenoglio JJ Jr: Characterization of the inflammatory infiltrate in human myocarditis-An endomyocardial biopsy study. In Bolte, H-D, editor: Viral heart disease. New York, 1984, SpringerVerlag, p. 74. 38. Huber SA, Lodge PA, Job LP: The role of virusand immune-mediated cardiocyte injury in coxsackievirus B3induced myocarditis. In Bolte, H-D, editor: Viral heart disease. New York, 1984, Springer-Verlag, p. 64. 39. Woodruff JF, Woodruff JJ: Involvement of T lymphocytes in

Heart

1985 Journal

the pathogenesis of coxsackie virus B3 heart disease. J Immunol 113:1726, 1974. 40. Guthrie M, Lodge PA, Huber SA: Cardiac injury in myocarditis induced by coxsackievirus group B, type 3 in Balb/c mice is mediated by lyt 2f cytolytic lymphocytes. Cell Immunol 88:558, 1984. 41. Huber SA, Lodge PA: Coxsackievirus B-3 myocarditis in Balb/c mice. Evidence for autoimmunity to myocyte antigens. Am J Path01 118:21, 1984.

Distal coronary artery perfusion during percutaneous transluminal coronary angioplasty Perfusion of the coronary artery distal to an occluding angioplasty balloon was performed in 34 patients undergoing coronary angioplasty (PTCA). A randomized crossover study was employed using two exogenous substances as perfusates: lactated Ringer’s solution (LR) and a fluorocarbon emulsion (FL), Fluosol-DA 20%. Both substances are electrolyte solutions, but the FL will dissolve more oxygen than the LB During two attempted coronary artery occlusions of 90 seconds each, we perfused through the central lumen (guidewire channel) of the PTCA catheter at 60 ml/min. With FL perfusion the mean time to onset of angina after occlusion was delayed (41 + 21 vs 33 f 16 seconds, mean +- SD; p < 0.05), the mean duration of angina was shortened (77 i 58 vs 92 ? 70 seconds, p < 0.05), and the rise in the ST segment of the ECG was reduced (0.15 + 0.24 vs 0.2 f 0.23 mV, p < 0.001) when compared to LR perfusion. Balloon occlusion time was able to be extended with FL perfusion (71 i 22 vs 59 2 22 seconds p < 0.001). These results indicate that perfusion of the distal coronary artery is possible during PTCA and can reduce ischemia during a prolonged balloon occlusion time. (AM HEART J 110:720, 1985.)

H. Vernon Anderson, M.D., Pierre P. Leimgruber, Diana L. Nelson, R.N., and Andreas R. Gruentzig,

Prolongation of balloon occlusion time may improve the remolding of plaque during percutaneous transluminal coronary angioplasty (PTCA).‘s2 In most patients, balloon occlusion is limited by the chest pain or electrical instability of ischemia in the myocardium distal to the occluding angioplasty balloon.3-7 Therefore, before the effect of longer balloon occlusion can be adequately tested, it is necessary to examine methods of reducing myocardial ischemia.

From

Emory

Received

University

School

for publication

Apr.

Reprint requests: Andreas cular Medicine, Emory Atlanta, GA 30322. *Overseas lia.

720

Research

Scholar

df Medicine. 8, 1985;

accepted

May

R. Gruentzig, M.D., University Hospital, of the National

15, 1985.

Interventional 1364 Clifton

Heart

Foundation

CardiovasRd., N.E., of Austra-

M.D., Gary S. Roubin, M.D. AtZanta, Ga.

M.B., B.S.,*

One method of reducing ischemia is to perfuse arterial blood through the central lumen of the angioplasty catheter during balloon occlusion. This technique has been tested in dogs’ and in humans.g Its disadvantages-high viscosity, hemolysis, and additional arterial access-led us to consider alternative perfusates. Fluorocarbon emulsions are a group of acellular substances with the capacity to dissolve large quantities of oxygen.‘O They have been found beneficial in experimental myocardial ischemia”, l2 and cerebral ischemia,13 and clinically useful in the anemic, perioperative state.14* l5 We undertook this study to determine if coronary artery perfusion with an oxygen-carrying fluorocarbon emulsion could be performed with current catheters during PTCA and whether such perfusion would reduce myocardial ischemia and would permit longer balloon occlusion time.

Volume

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METHODS

Patients undergoing routine elective coronary angioplasty at Emory University Hospital formed the population base.Selection criteria for inviting patients to participate in the study were the following: singlestenosisof the proximal portion of a major coronary artery (preferably the left anterior descending), no other significant coronary artery disease,and good left ventricular function on referral angiographic study. Thirty-four patients (30 men, 4 women) with a mean age of 58 years (range 37 to 78 years) participated in the study. All patients gave written informed consent under a protocol approved by our institutional Human Investigations Committee. The involved vessels were the left anterior descendingcoronary artery (LAD) in 31 patients and the right coronary artery (RCA) in two patients. One patient underwent dilatation of an LAD graft stenosis. Study design. The study wasperformed using a singleblind, randomized, crossover protocol. PTCA was performed via the right femoral artery technique in a standard manner.‘” All patients underwent one or two brief balloon occlusionsat the site of the stenosisto verify that the lesion was responsiveto balloon dilatation. Patients were then randomly assignedto distal coronary artery perfusion with either lactated Ringer’s solution (LR) or fluorocarbon emulsion (FL) during an attempted balloon occlusion time of 90 seconds.Balloon occlusion time was measuredwith a stopwatch. After balloon deflation, the patient rested for 2 to 5 minutes. When any angina present had completely subsided and the ST segments and the pulmonary artery wedgepressurehad returned to baseline values, the patient was crossedover to repeat occlusionand perfusion with the other substance.All patients received heparin, 10,000units intravenously, nitroglycerin, 400pg, and nifedipine, 10 mg sublingually, at the beginningof their procedures.Atropine and diazepamwere usedasneededfor anticholinergic and sedativeeffects. Perfusate preparation. LR and FL (Fluosol-DA 20%, Alpha Therapeutic Corporation, Los Angeles, Calif.) were usedas perfusates. Both are electrolyte solutions, but the fluorocarbon contains more calcium (5 mEq/L vs 3 mEq/ L), and in addition contains magnesium(2.1 mEq/L) as well as emulsified fluorocarbon particles (20 gm/dl) that increase its oxygen carrying capacity (Table I). When equilibrated to a gas mixture of 95% oxygen and 5% carbon dioxide, the fluorocarbon emulsion contains approximately 7 volume percent oxygen. The lactated Ringer’s solution, equilibrated to 100% oxygen, contains only approximately 2.5 volume percent oxygen.lO,l” Both perfusateswere prepared by passinggasthrough a 0.2 pm filter and bubbling it through the liquids at room temperature-100% oxygen for the LR and 95% oxygen/ 5% carbon dioxide for the FL. The oxygenated liquids were drawn up into separate angiographic injector syringes, sealed with closed stopcocks, and placed in an angiographic injector (Mark IV, Medrad, Inc., Pittsburg, Pa.). The warming jacket wasplaced around each syringe barrel, where it remained. No further attempts were made to monitor temperature. Study population.

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perfusion

PTCA

during

721

I. Comparison of electrolyte and fluorocarbon concentration of perfusates Table

Substance

LIZ

FL

-Sodium Potassium Chloride Calcium Bicarbonate Lactate Magnesium Fluorocarbon

1:io 4 109 3

128 4.6 II”.:!

-5 0 “5

‘8 2.1

20 gm/lW

ml

~..LR = lactated 20’< ).

Ringer’s

solution:

FL = fluorocarbon

rmulsion

(Fluwx~l-DA

Catheter perfusion. The central lumen of the angioplasty catheter (Gruentzig Dilaca, USCI, Billerica, Mass.) wasusedto deliver perfusate to the coronary artery distal to the occluding balloon. The Y-connector on the proximal port of the central lumen was fitted with a three-way stopcock. One input port was connected to a pressure transducer and the other was connected through high pressuretubing to the angiographic injector syringe loaded with perfusate. All studies were performed with an 0.014or 0.016guidewire in position in the central lumen of the angioplasty catheter, with the guidewire tip extending out of the catheter into the distal segment of the artery. Flow rate. The flow rate for perfusate (60 ml/min) was calculated based on estimates of oxygen delivery to the myocardium. Average myocardial oxygen consumption was estimated to be 9 ml O,/min/lOO gm.‘;,‘” Assuming that an occlusion of the proximal portion of a major coronary artery removesone third of the supply of oxygen, it was estimated that % x 9 = 3 ml O,/min/lOO gm was needed for the myocardium distal to the occluding balloon. With left ventricular massestimated at 160 gm,l!’ approximately 3 X 1.6 = 4.8 ml/min of oxygen would be needed. If the fluorocarbon emulsion were to supply this oxygen from a content of 7 volume percent (7 ml O,/lOO ml), a flow rate of 4.810.07=*68.6ml/min would be needed. By comparison,the lactated Ringer’s solution would need to flow at 4.8/0.025 = 192 ml/min to supply the same amount of oxygen. The flow rate chosen,60 ml/min, is in the lower range acceptedfor normal coronary artery flow2” and wasthought to be acceptablefor atherosclerotic arteries. The catheters and guidewires were tested and were found to require 150to 300psi perfusion pressurefrom the injector in order to drive the perfusate through the assembledcatheter at 60 ml/min. Angina grade. Study patients were interviewed the evening before PTCA and were asked to grade on a scale of 0 to 10 any chest discomfort they had previously experienced. The location and quality of their previous angina was carefully noted. Patients were informed that they would be asked periodically during the procedure to grade their chest discomfort, but would not be told when

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34 PATIENTS t n = 15

-

Randomize

I

n=2 Perfusion with -Arrhythmia Saline (LR)

Perfusion Fluorocarbon

with

-

n = 19

n=3 I

I Perfusion Fluorocarbon

with (FL)

Perfusion with Saline (LR)

(FL)

1985

Heart Journal

The PAWP was measured from recorded tracings before and at the end of balloon occlusion.Similar to the adjustment madefor the ST segmentof the ECG, we also adjusted the rise in PAWP by dividing it by balloon occlusion time (mm Hg/t). This adjusted measurewith time as the denominator was called PAWP rate. Statistical analysis. Results are expressedas mean tSD unless otherwise noted. Comparison was made between measurementson each patient during his or her LR perfusion and during his or her FL perfusion using a paired t test. Order of perfusion effects was tested by comparing LR as first perfusion with LR as second perfusion, and FL as first. perfusion with FL as second perfusion, usingan unpaired t test. A probability (p) value lessthan 0.05 was consideredsignificant. RESULTS

n = 16 complete

n = 13 complete

Fig.

1. Study protocol.

balloon inflation or deflation occurred or which perfusate they were receiving. During the two attempted 90-secondballoon occlusions, the time from balloon inflation to onset of angina, the duration of angina, and the intensity of angina (0 to 10) were recorded. To allow comparison of less intense but longer-lasting angina signifying equivalent ischemia, we constructed the intensity-duration product by multiplying the maximum intensity of angina by the duration of angina (grade x set). Because balloon occlusion times were different for each patient, we also divided the intensity-duration product ,by balloon occlusion time (grade x se&). This adjusted measure,having time asthe denominator, wascalled the angina rate sinceit expressed a measureof angina per second of occlusion. Electrocardiography. ECG leadswere placed ta obtain leads II and V,. The ECG and monitored pressureswere displayed and recorded with an automated recording system (MEDARRS, Honeywell, Inc, Denver, Colo.). From the recorded tracing the character of the T wave (upright or inverted) and the level of the ST segmentin millivolts (mV) wasmeasuredbefore balloon occlusion,30 secondsafter balloon occlusion, and at the end of balloon occlusion. We also adjusted the rise in the ST segmentby dividing it by balloon occlusion time (mV/t). This adjusted measure,with time asthe denominator, was called the ST segment,rate since it expresseda measureof the ST segmentrise per secondof occlusion. Hemodynamics. Aortic pressure was monitored from the guiding catheter and distal coronary artery pressure was monitored from the central lumen of the angioplasty catheter (when distal perfusion was not taking place). In 19 patients (all LAD occlusions) either a No. 7F SwanGanz or a Myler pacing catheter was placed in the pulmonary artery for measurement of the pulmonary artery wedge pressure (PAWP). All pressures were obtained with saline-filled tubing and strain-gaugetransducers (Statham P23ID).

Fifteen patients were randomized to receive LR first and 19 patients to receive FL first (Fig. 1). Five patients developed ventricular fibrillation (VF) during their first study occlusions. In three patients VF occurred with FL perfusion at 14,40, and 55 seconds following balloon occlusion. In two patients VF occurred with LR perfusion at 48 and 50 seconds following balloon occlusion. All patients were cardioverted and had successful PTCA with no other complications following the procedure. These patients did not complete the study and were excluded from subsequent analysis. Thus 29 patients completed both study occlusions. Angina (Table II). Six patients had more rapid onset of angina with FL perfusion, while 18 patients developed angina more rapidly with LR perfusion. Five patients had onset of angina at the same time with both perfusions, or had no angina. The mean time to onset of angina was 33 + 16 seconds with LR perfusion and 41 k 21 seconds with FL perfusion tp < 0.05). Seven patients had more severe angina during FL perfusion, 15 patients had more severe angina during LR perfusion, and seven patients had the same severity of angina during both perfusions (three of these seven had no angina during either perfusion). The mean maximum angina grade was reduced from 6 + 3 during LR perfusion to 5 f 3 during FL perfusion 0, < 0.05). In seven patients angina persisted longer after FL perfusion, while in 18 patients it persisted longer after LR perfusion. Three patients had no angina and one patient was uncertain about the disappearance of mild angina and was therefore not included. The mean duration of angina was shortened from 92 + 70 seconds with LR perfusion to 77 +- 58 seconds with FL perfusion (p <‘0.05). ‘The product of the maximum intensity of angina

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Coronary

perfusion

II. Angina variables and balloon occlusion time during study occlusions

Table

during

-.- -..-

PTCA

723

.-..-

Perfusate

Time to onset of angina after balloon occlusion (set) Maximum intensity of angina Total duration of angina (set) Intensity-duration product (grade x set) Angina rate (grade X se&) Balloon occlusion time (set) LR = lactated

Table

Ringer’s

solution;

(O-10)

FL = fluorocarbon

LR

FL

Diff

,I

I’

33 rt 16

41 +- 21

+8 -t 17

2;;

<0.05

6+-3 92 k 70 657 +- 675

.5 t 3 77 t 58 465 -+ 467

-1 -13 -196

+- 2 + 44 t 363

“9 2x 2x

a.05 -co.05 <0.005

13 f 14 59 + 22

7*8 71 + 22

-5 +11

+- 8 i- 18

28 29


emulsion;

Diff = paired difference.

III. ECG and hemodynamic indices during study occlusions Perfusate

ST segment

rate (mV/sec X 10w3) PAWP rate (mm Hghec X lo-*)

LR = lactated

Ringer’s

solution;

LR

FL

4.4 * 5.9

3.1 + 6.3

12 + 10

10 + 7

FL = fluorocarbon

emulsion;

Diff = paired difference;

the duration of angina was reduced from 657 + 675 during LR perfusion to 465 + 467 during FL perfusion (p < 0.005). All nine patients who had a product greater than the mean (657) with LR perfusion had lower products with FL perfusion. The angina rate (intensity-duration product divided by balloon occlusion time) was reduced from 13 f 14 during LR perfusion to 7 + 8 during FL perfusion (p < 0.001). All 10 patients who had higher than the mean (13) angina rate with LR perfusion had lower rates with FL perfusion. Electrocardiogram. Of the 29 patients who completed both perfusions, an adequate tracing was obtained during LR perfusion in 26; recordings were technically unsatisfactory in two patients and one patient had a left bundle branch block (LBBB). An adequate tracing was obtained in 28 of 29 patients during FL perfusion; the patient with LBBB was excluded. With LR perfusion, 4 of 26 patients (15%) had upright T waves at balloon deflation, and with FL perfusion 17 of 28 patients (61%) had upright T waves at balloon deflation (x” = 9.8, p < 0.005). The mean ST segment elevation was 0.2 + 0.23 mV in 59 +- 22 seconds with LR perfusion, and 0.15 -t 0.24 mV in 71 & 22 seconds with FL perfusion (p < 0.001, Fig. 2, upper panel). The ST segment rate (ST segment rise divided by balloon occlusion time, mV/t) is shown in Table III. with

Diff -1.3 -2

I1

P

f 2.2

26

<0.005

Y!z 5

19

<0.05

PAWP = pulmonary

artery

wedge pressure.

Four patients had higher rates with FL than with LR perfusion, 17 patients had higher rates with LR than with FL perfusion, and five patients had the same rate (four of these five patients had no ST segment rise with either perfusion). Pulmonary artery wedge preswre. During LR perfusion, the PAWP rose by a mean 5.4 + 0.7 mm Hg. During FL perfusion, the PAWP rose by a mean 5.7 + 0.7 mm Hg. Although the amount of rise was the same, the time during which the PAWP rose was significantly different (57 k 22 seconds vs 67 -t 24 seconds, p < 0.05; Fig. 2, lower panel). The effect of this time factor is seen in the PAWP rate (PAWP rise divided by balloon occlusion time, mm Hg/t>, shown in Table III. Five patients had higher rates with FL than with LR perfusion, 12 patients had higher rates with LR than with FL perfusion, and two patients had the same rate (both had no PAWP rise with either perfusion). Balloon occlusion time. Fourteen patients (48%) tolerated the target 90-second occlusion with FL perfusion, while with LR perfusion only seven patients (24%) tolerated the full occlusion period. The mean occlusion time was 59 r 22 seconds during LR perfusion and 71 f 22 seconds during FL perfusion @I < 0.001, Table II). Order of perfusion effect. There was no significant difference based upon order of perfusion in any variable except for time to onset of angina following

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I 0.20

plasty

T

1

I ,

IV. Duration of balloon occlusionin coronary angio-

Table

0.301

/’

I’ +

,/’

1

T

Reference

0.15-

E

Kaltenbach et al.2 Rothman et al.) Feldman et aL4 Serruys et al.’ Simon et al.”

O.lOA=LR 0= FL

0.05,‘/’

October, 1985 Heart Journal

,, f/’

Number patients

250 15

21 33 26

of

Balloon occlusion time (seconds, as reported)

5 - 60 (range) 9.8 k 3.7 (mean + SD) 20 - 70 (range) 51 k 12 (mean k SD) 30 - 60 (range)

Y

1

0

10

20

30

40

50

60

I

70

00

Time(sec)

25 1

G 24 i

M ?! 0

kLR 0= FL

501,

0

10

20

30

40

50

lime

(set)

60

70

1 80

Fig. 2. Upper panel, Comparative rise in ST segments and balloon occlusion times during study occlusions. Lower panel, Comparative rise in pulmonary artery wedge pressureand balloon occlusion times during study occlusions.LR = Lactated Ringer’ssolution; FL = fluorocarbon emulsion.Brackets indicate + SEM.

balloon occlusion. Onset occurred more rapidly when LR was the second rather than the first perfusate (26 + 11 seconds vs 42 +- 18 seconds, p < 0.05). Clinical outcome. All 29 patients who completed the study had successful PTCA. The angiographic diameter stenosis was reduced from 77 + 12% to 23 & 8% and the tram+stenotic pressure gradient was reduced from 50 +- 12 mm Hg to 13 f 5 mm Hg. In two patients coronary dissection without occlusion of the artery was noted and in five patients an intimal tear occurred. All seven patients had uneventful post PTCA courses. Routine ECGs at 0,8, and 16 hours following the procedure were unchanged in all patients. One asymptomatic patient had a slight increase in creatine kinase (CK) and its MB isoenzyme (CK-MB), with peak CK = 360 IU/L and peak CK-MB = 18 % . This patient had an uneventful course and was discharged home at the routine time. Long-term follow-up. Information was available on

33 of the 34 patients who entered the study. Of the five patients who did not complete the protocol, four underwent repeat cardiac catheterization 6+ 1 months following PTCA. One patient was asymptomatic and declined catheterization. Three of the four patients who underwent restudy were judged to have continuing success and one was judged to have restenosis. Of the 29 patients who did complete the protocol, 20 underwent repeat cardiac catheterization 7 f 2 months following PTCA. Three patients with a negative exercise test and four patients who were asymptomatic declined restudy, as did one patient with a positive exercise test. One patient was lost to follow-up. Fifteen of the 20 patients (75 % ) who were restudied were judged to have continuing success and five (25%) were judged to have restenosis. DISCUSSION

This study shows that coronary artery perfusion distal to the occluding angioplasty balloon can be accomplished with oxygenated liquids during PTCA and may have a beneficial effect by reducing myocardial ischemia and prolonging balloon occlusion time. Coronary perfusion. The concept of coronary artery perfusion during PTCA is not new. Perfusion through the catheter, typically with the patient’s femoral artery blood, was anticipated early in the history of angioplasty?,21s22 Once it was learned that brief occlusions of a coronary artery were well tolerated and that perfusion was not necessary in order to have a successful procedure, perfusion was discontinued.23 Recent interest in the cumulative ischemic effects of sequential coronary artery occlusions24-27has led us to reexamine this problem. Meier et al.* demonstrated in dogs that perfusion of femoral artery blood through a roller pump and current angioplasty catheter could support the canine myocardium for 60 minutes of coronary artery occlusion. Hemolysis occuring in the narrow catheter channel was noted and (importantly) in order to achieve a physiologic flow rate, the guide-

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wire had to be withdrawn most of the length of the catheter. Spears et al.28 demonstrated in dogs that a fluorocarbon emulsion could be perfused through an angioplasty catheter and could support the canine myocardium during occlusions lasting up to 19 minutes. The flow rates achieved (mean = 19 ml/ min) were probably subphysiologic for human coronary arteries. In contrast, using a standard angioplasty catheter, we were able to achieve physiologic flow rates (60 ml/min) with the guidewire extended out the end of the catheter. Ischemia. It is important to note that neither perfusate completely prevented ischemia. The data indicate that fluorocarbon emulsion, with its higher oxygen content, was superior to a saline solution in reducing ischemia at the flow rate studied. The differences in the variables we measured, although significant, were not large. Differences were consistent, however, and patients with the highest measures of ischemia during LR perfusion had the most marked reductions during FL perfusion. This suggests that the higher oxygen content of the fluorocarbon emulsion was able to better maintain aerobic metabolism of the myocardium than the saline solution. Preservation of aerobic metabolism was the apparent mechanism in other studies of experimental myocardial ischemia.“, l2 It is possible that the flow rate we chose was too low to completely support aerobic metabolism. Alternatively, side branches may have been occluded by the inflated balloon so that their territory became ischemic. Prolonged occlusion. The duration of balloon occlusion in coronary angioplasty is influenced by the operator’s assessment of patient tolerance, including severity of angina, amount of ischemic change on the ECG monitor, occurrence of arrhythmias, or fall in arterial pressure. Although no specific studies of patient tolerance of balloon occlusion times have been reported, evidence from the literature2-6 suggests that most operators limit balloon occlusion time to 30 to 60 seconds and that this corresponds to the onset of angina, occurrence of electrical instability, or depression of hemodynamics (Table IV). To test the influence of perfusion on balloon occlusion time we set a goal of 90 seconds, 50% to 100% longer than commonly reported. Our finding that average occlusion time was 59 seconds with LR perfusion is in accord with other reported occlusion times when there was no perfusion, and suggests that perfusion alone has no effect on reducing myocardial ischemia. In this small sample of 29 patients, the angiographic restenosis rate was 25%. This result is similar to the general angioplasty experience,2g and

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PTCA

725

suggests that even longer coronary occlusions than we were able to obtain may be necessary to adequately study the influence of prolonged balloon occlusion on restenosis. Recovery. The patients rested for 2 to 5 minutes between study occlusions and during that time angina subsided, and the ST segments and pulmonary artery wedge pressure returned to baseline. If recovery time was incomplete, then an order effect might have been seen; those patients who received FL first might have had less ischemia and a better recovery than those patients who received LR first. No significant order of perfusion difference was seen in any variable except the onset of angina when LR was the second instead of the first perfusion. This suggests that sufficient recovery time had elapsed. Complications. Ventricular fibrillation (VF) occurred in 5 of 34 (15% ) of our patients. This is approximately seven times higher than the general incidence during angioplasty.“” The mechanism for this is unclear and requires further investigation. It may have been related to perfusate temperature, electrolyte concentrations, or occluded side branches. The incidence of VF was similar with both perfusates and occurred 40 to 50 seconds following balloon occlusion. Although the ECG tracings revealed some ischemia prior to the onset of VF in all five patients, frequent ventricular ectopic beats also immediately preceded the event. Despite this, the patients had successful cardioversion and angioplasty, and an uncomplicated post procedure course. All 29 patients completing the study also had successful PTCA. Two patients had coronary dissections without occlusion and five patients had intimal tears. One patient demonstrated a slight rise in CK-Ml3 isoenzyme. These findings are similar to the general angioplasty experience.“” Conclusions. We perfused the coronary artery distal to an occluding angioplasty balloon twice during PTCA by pumping exogenous fluid through the central lumen of the angioplasty catheter. For each perfusion an electrolyte solution was used, but one solution had an additional component, fluorocarbon particles, that increased its oxygen carrying capacity. During an attempted occlusion time of 90 seconds a significant reduction occurred in the onset, intensity, and duration of angina, ischemic response of the ECG, and rise in pulmonary artery wedge pressure when fluorocarbon instead of saline was perfused. As a result, balloon occlusion time was significantly longer with fluorocarbon perfusion. This study demonstrates that perfusion of the coronary artery during angioplasty is easily accom-

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plished and deserves further consideration as a method to reduce ischemia during prolonged balloon occlusion. REFERENCES

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October, 1985 Heart Journal

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