Effects of intraaortic balloon pumping on coronary hemodynamics after coronary angioplasty in patients with acute myocardial infarction It has been reported that intraaortic balloon pumping can prevent reocclusion after coronary angioplasty for acute myocardial infarction. The speculated mechanism has been the production of markedly enhanced diastolic coronary perfusion pressure; however, most studies have reported that intraaortic balloon pumping has little effect on coronary blood flow. To assess the effectiveness of this procedure, we studied 12 patients with acute anterior myocardial infarction who were undergoing coronary angioplasty and intraaortic balloon pumping. After successful angioplasty, coronary blood flow velocity was measured with a coronary Doppler catheter before and during intraaortic balloon pumping. Although mean coronary blood flow velocity was unchanged, intraaortic balloon pumping increased peak coronary blood flow velocity from 34.6 * 5.0 cmlsec (mean + SEM) to 46.7 r 5.8 cmlsec (p < 0.005). Such an increase in peak coronary blood flow velocity seemed to be a mechanism by which intraaottic balloon pumping could prevent reocclusion after coronary angioplasty for acute myocardial infarction. (AM HEART J 1992;124:1133.)

Masaharu Ishihara, MD, Hikaru Sato, MD, Hironobu Tateishi, MD, Takuji Kawagoe, MD, Yuji Muraoka, MD, and Mitsuisa Yoshimura, MD Hiroshima, Japan

Intraaortic balloon pumping has been used since 1968 for treatment of patients with cardiogenic shock and refractory left ventricular failure that resulted from acute myocardial infarction.l, 2 Recent studies have demonstrated that intraaortic balloon pumping may also be useful in the treatment of patients with uncomplicated myocardial infarction who are undergoing reperfusion therapy, and it has been associated with a reduced incidence of coronary reocclusion.3-5 Although the speculated mechanism by which intraaortic balloon pumping could prevent reocclusion was the production of markedly enhanced diastolic coronary perfusion pressure,5 most studies have reported that intraaortic balloon pumping has little effect on coronary perfusion in patients with normal blood pressure,‘. ’ and little information on patients with acute myocardial infarction who are undergoing From the Department Japan. Received Reprint roshima

for publication

of Cardiology,

Hiroshima

Jan. 16. 1992; accepted

City May

Hospital,

Hiroshima,

8, 1992.

requests: Masaharu Ishihara, MD, Department of Cardiology. HiCity Hospital. 7.33, Mote-machi, Naka-ku, Hiroshima, 730 Japan.

-4~1140544

reperfusion therapy is available. We therefore undertook this study to assess the effects of intraaortic balloon pumping on coronary blood flow of the infarct artery that was recanalized by coronary angioplasty in patients with uncomplicated myocardial infarction. METHODS Patients.

The study group consisted of 12 patients with acute anterior myocardial infarction who were undergoing emergency coronary angioplasty and intraaortic balloon pumping. Informed consent was obtained from each patient and from each patient’s closest relative for intraaortic balloon pumping and for the coronary Doppler echocar-

diographic measurements. Cardiac catheterization. In all patients, the Judkins approach via the right femoral artery was used for ventriculography and coronary angiography. After vascular access was obtained, 5000 U of heparin was administered. Left ventriculography was performed in the 30-degree right an-

terior oblique projection, and the left ventricular ejection fraction was calculated with the area-length method.* Left ventricular end-diastolic pressure was measured by means of a pig-tail catheter before ventriculography. Selective coronary angiography was performed in multiple projec1133

November

1134

Ishihara

et al.

American

1

\

“-

\ ,i

.,:

advanced through an 8F angioplasty guiding catheter over a 0.014 inch guide wire into the left anterior descending artery and positioned immediately proximal to the infarct lesion. Coronary blood flow velocity without intraaortic balloon pumping was measured first. After stable signals of coronary blood flow velocity were obtained, intraaortic balloon pumping was initiated with the balloon pump rate at l:l, and continuous recording was done for 5 minutes. Mean and phasic signals of coronary blood flow velocity, arterial pressure that was cjbtained via the guiding catheter, and the ECG were continuously recorded on a multichannel direct-writing recorder. Diameter of the target coronary artery was measured with a hand-held caliper be fore and during intraaortic balloon pumping.” Data analysis. The systolic flow velocity integral (area from the systolic aortic upstroke to the aortic dicrotic notch under the Doppler velocity signal) (Fig. 1) was computed, and mean systolic coronary blood flow velocity was calculated as the quotient of the systolic flow velocity integral and systolic time. The diastolic flow velocity integral (area from the aortic dicrotic notch to the systolic aortic upstroke under the Doppler velocity signal) was computed, and mean diastolic coronary blood flow velocity was calculated as the quotient of the diastolic flow velocity integral and diastolic time. Statistical analysis was performed with the paired t test. Differences were considered significant if the p value was less than 0.05. All data are expressed as means k SEM. RESULTS Patient

Fig. 1. Analysis of coronary Doppler velocity signal. Mean systolic flow velocity was calculated as the quotient of the systolic flow velocity integral (sl), bounded by the systolic upstroke to the dicrotic notch and systolic time (ST). Mean diastolic flow velocity was calculated as the quotient of the diastolic flow velocity integral (dI) and diastolic time (DT). CBFV, Coronary blood flow velocity; pV, peak coronary blood flow velocity.

tions. After initial angiography, 0.5 mg of nitroglycerin was infused into the left coronary ostium, and tissue plasminogen activator was infused intravenously for over 60 minutes. After thrombolysis, an additional 5000 U of heparin was administered, and coronary angioplasty was performed in a conventional manner with a balloon that was chosen to approximate the size of adjacent, nondiseased arterial segments. After coronary angioplasty, there was no significant residual stenosis (defined as stenosis of 2 50cr luminal diameter narrowing). A 9F intraaortic balloon (Kontron Instruments SA, Everett, Mass. ) was placed percutaneously from the left femoral artery. Measurements of coronary blood flow velocity. After the final balloon inflation, the coronary Doppler study was performed. Coronary blood flow velocity was measured with a 3F coronary Doppler catheter (Millar Mikro Tip 20 MHz Doppler catheter, model DC-101, Millar Instruments, Inc., Houston, Texas).g The coronary Doppler catheter was

1992

Heart Journal

Ten men and two women, characteristics. with a mean age of 56 f 3 years, were included in the study. All patients were in Killip class I at the time of admission to the hospital. At t,he time of initial angiography, nine patients had a total occlusion and three patients had a subtotal occlusion in the proximal left anterior descending artery; angiographically visible collateral vessels that supply the left anterior descending artery region were present in six patients. Left ventricular end-diastolic pressure was 24 AI 2 mm Hg, and left ventricular ejection fraction was 51”;’ -t 95:;. Emergency coronary angioplasty was successfully performed within 12 hours (6.3 + 1.1 hours) after the onset of chest pain, which resulted in residual stenosis of less than 50”; luminal diameter narrowing (29 “C -+ 5 9; ). Systemic hemodynamics (Table I). Intraaortic balloon pumping increased mean diastolic arterial pressure (98 k 4 mm Hg to 109 + 5 mm Hg; p < 0.001). Significant decreases were observed in mean systolic arterial pressure (117 i 6 mm Hg to 100 t 5 mm Hg; p < 0.001) and rate-pressure product (11.4 t 0.8 X 10” mm Hg . beats/min to 9.9 + 0.7 X lo3 mm Hg . beats/min; p < 0.001). No significant changes were noted in mean arterial pressure (106 f 5 mm Hg to 105 + 5 mm Hg) and heart rate (85 + 3 beats/ min

t,o 86 + 2 beats/min).

Volume 124 Number 5

IABP after PTCA

in

AMI

1135

60, 3 -2

Mean Coronary

IABP IABP

Mean Blood

Systolic

Mean

Diastolic

Flow Velocity

2. Bar graph showing effects of intraaortic balloon pumping (IABP) on coronary blood flow velocity.

*p < 0.005;

Table

Before During

i

Peak

Fig.

D m

**p

< 0.02.

1. Systemic hemodynamics in individual patients Peak systolic AP (mm Hgl Patient NO.

1 2 3 4 5 6 7 8 9 LO 11 12

Mean +-SEM

Mean diastolic AP (mm Hg)

Mean

AP

Heart rate (beatslmin)

(mm Hgl

Before IABP

During IABP

Before IABP

During IABP

Before IABP

During IABP

Before IABP

130 130 169 148 95 138 120 179 157 111 105 116 133 7

104 96 138 122 90 119 102 156 147 94 96 109 114* 6

90 96 117 115 77 97 85 122 117 76 92 88 98 4

100 104 127 118 87 111 93 141 136 87 94 105 109* 5

101 105 134 123 80 107 90 134 124 a5 95 93 106 5

96 98 124 116 85 106 86 137 132 84 93 101 105 5

79 105 94 83 74 98 76 88 80 82 88 71 85 3

AP, Arterial pressure; IABP, intraaortic *p < 0.001 versus before IARP.

balloon

During IABP 75 103 92 87 76 94 a0 96 83 80 87 7 86 2

pumping.

Coronary blood flow velocity. Effects of intraaortic balloon pumping on coronary blood flow velocity are shown in Figs. 2 and 3 and in Table II. Intraaortic balloon pumping increased peak coronary blood flow velocity (from 34.6 i 5.0 cm/see to 46.7 +- 5.8 cm/ set; p < 0.005), whereas mean coronary blood flow velocity was unchanged (from 16.3 ? 3.4 cmlsec to 16.6 f 3.3 cm/set). Observations of the coronary blood flow velocity pattern showed that intraaortic balloon pumping increased mean diastolic coronary blood flow velocity (from 23.5 f 4.3 cmlsec to 25.8 -t 4.4 cm/set; p < 0.02) and decreased mean

systolic coronary blood flow velocity (from 6.3 a 2.8 cm/set to 3.1 + 2.3 cm/set; p < 0.005). There was no significant change in diameter of the target coronary artery before and during intraaortic balloon pumping (from 3.4 t 0.2 mm to 3.3 + 0.2 mm). DISCUSSION

Recent studies have shown that intraaortic balloon pumping is useful not only in the treatment of patients with cardiogenic shock19 ‘, but also in the treatment of patients with uncomplicated myocardial infarction who are undergoing reperfusion ther-

November

1136

Ishihara

American

et al.

Table II. Coronary blood flow velocity in individual patients

Before IABP

Mean CBFV fcmiseci

Peak CBFV (cmisec)

Before IABP

During IABP

Before IABP

1 2 3 4 5 6

59.0 42.0 10.3 16.8 21.5 23.8

65.5 80.0

39.8 25.0

31.3

6.6

24.5 24.0 28.5

fi.9

7.8

6.5 lo..5

6.7

7 8 9

29.5

39.8

4.4

10

65.0 46.5 32.0

68.8 67.0 49.5

11

19.8

‘1.0

12

48.5 34.6 5.0

60.8 46.7* 5.8

31.4 'S.7 8.6 4.3 25.9 16.3 3.4

Putiatient

ECG

nv.

Mean

k SEM

CBFV, Coronary

*p