Catheterization and Cardiovascular Diagnosis 16:164-167 (1989)

Case Reports

Coronary Air Embolism During Coronary Angioplasty

Stavros Hadjimiltiades, MD, Thomas S. Goldbaum, MD, Ed Mostel, MD, Gary S. Mink, MD, and Demetrios Kimbiris, MD

A case is described in which the use of the Hartzler microcatheter during coronary angioplasty resulted in coronary air embolism. The recognition, prevention, and mech- anism of this occurrence are discussed.

Key words: Hartzler microcatheter, chest pain, ST segment elevation

INTRODUCTION

Air embolism during coronary artery angioplasty can occur during catheter injections because of improper flushing of the coronary manifold or rarely because of a defect of the dilating balloon [l] . In this case report we describe the occurrence of chest pain and ST segment elevation during coronary angioplasty that is best ex- plained by coronary air embolism. The unique construc- tion of the Hartzler microcatheter venting system contributed to this phenomenon.

CASE REPORT

This 45-year-old man developed an inferior myocar- dial infarction in January 1988. Coronary angiography revealed a codominant coronary artery distribution with a 90-95% stenosis at the origin of a large posterolateral branch supplied by the left circumflex coronary artery. The left anterior descending coronary artery was normal. The right coronary artery had a proximal 70% stenosis (Fig. IA). Because of the existence of angina despite vigorous medical treatment, coronary angioplasty was

Initially the stenosis of the posterolateral branch of the left circumflex was dilated with a 2.5-mm Hartzler micro XT catheter, which was inflated up to 7 atmospheres with partial improvement, and then exchanged for a 3.0 mm Hartzler microcatheter, which was inflated to a maxi- mum of 8 atmospheres. There was marked improvement in luminal diameter with a decrease in stenosis diameter to 3 0 4 % . The antegrade flow was excellent, and the system was removed. An 8-F JR4 guiding catheter was then positioned at the ostium of the right coronary artery, and the same 3.0-mm Hartzler microcatheter was ad- vanced into the right coronary artery. The time period during which the Hartzler microcatheter was exposed to air outside the body of the patient was approximately 20 minutes.

perfolltled.

During the initial inflation the balloon did not appear to expand completely. The distal portion of the dilatation catheter was radiolucent, and the proximal portion was radiodense. The pressure was increased to 8 atrno- spheres, at which point the balloon completely filled with contrast. When the balloon was deflated after 30 seconds the patient developed additional severe chest pain and persistent ST segment elevation. Contrast injection re- vealed sluggish and pulsatile flow with a blunt hazy leading edge in branches of the right coronary artery (Fig. I ) . Intracoronary nitroglycerin was given with no change in angiographic appearance. Over the next 10 minutes the ST segment elevation returned to baseline. Repeat coronary arteriography revealed that the proximal 70% right coronary artery stenosis decreased to 30% with excellent antegrade flow to all branches. There were no branch “cut off’ markings or staining suggestive of particulate embolism. Repeat arteriography of the left coronary artery revealed the posterolateral branch of the left circumflex artery to be widely patent.

The patient was returned to the coronary care unit, and there was no electrocardiographic or enzymatic evidence of myocardial damage.

DISCUSSION

Coronary air emboli are an uncommon yet known cause of chest pain and electrocardiographic changes that occur during cardiac catheterization and coronary angio- plasty [2]. Coronary air emboli occurring during coro- nary angioplasty may be related to introduction of air

From the Hahnemann University Hospital, Philadelphia.

Received June 29, 1988; revision September 9, 1988.

Address reprint requests lo Demetrios Kimbiris, M.D. , Hahnernann University - M.S. 110, Broad & Vine Sts., Philadelphia, PA 19102.

@ 1989 Alan R. Liss, Inc.

Coronary Air Embolism 165

Fig. 1. A: Left anterior oblique projection of the right coronary right coronary artery immediately following angioplasty. The artery demonstrating the proximal stenosis (arrow) prior to contrast stops abruptly in the right ventricular branches (ar- angioplasty. 6: Right anterior oblique projection of the right rows) but fills the distal vessel (not shown). D: During a later coronary artery demonstrating the right ventricular branches injection the flow of contrast stops further down in the right prior to angloplasty. C: Right anterior oblique projection of the ventrlcular branches (arrows).

166 Hadjimiltiades et al.

Fig. 2. A: Inside a contrast-filled plastic tubing a 3-mm Hartzler microcatheter can be seen inflated to 4 atmospheres. The air in the balloon was introduced by constant suction after the balloon was properly prepared. The appearance of the balloon at this level of pressure closely approximates the initial appear- ance of the balloon during its inflation in the right coronary artery. €3: As the inflation pressure increases the dilatation catheter fills with contrast and the air is compressed until it escapes through the venting port into the tubing (arrow). A column of approximately 0.2 mL of air formed.

through the guiding catheter, through a malfunctioning dilatation catheter [ l ] , or as in this case through the venting system used by the Hartzler microdilatation catheter.

The Hartzler microcatheter has a unique construction. A small venting port located at the tip of the catheter

permits the expulsion of air from the balloon as the balloon is being filled with contrast under constant pres- sure until a small amount of the contrast appears through the venting port. Owing to the small size of the port and the high viscosity of the contrast, the port is functionally sealed. The application of constant negative pressure can result in aspiration of air through the port despite the above-mentioned sealing mechanism. In our case the indeflator apparently was kept on negative pressure while the catheter was exposed to air. The subsequent complete inflation of the balloon in the coronary artery resulted in expulsion of air from the tip, which formed a column of air in the coronary artery. The deflation of the balloon and restoration of coronary flow was followed by migra- tion of air distally, giving the characteristic angiographic picture of initial coronary air embolism described by Heupler [3].

In Figure 2A a demonstration system using a contrast- filled plastic tubing and a 3.0-mm Hartzler microdilata- tion catheter revealed the angiographic appearance of a partially airfilled (arrow) dilatation catheter. As the infla- tion pressure increases, the dilatation catheter fills with contrast and the air is compressed until it escapes through the venting port into the tubing (Fig. 1B).

The time course of events is consistent with findings of experimental air embolism [4]. Depending on the solubility of the gas, the bubbles will keep the arterioles occluded until they are reabsorbed or pushed into the coronary sinus IS]. The period of occlusion depends on the level of the aortic pressure and the amount of gas present [2,6,7]. The presence of gas bubbles in the vas- cular tree is also associated with adhesion and consump- tion of platelets and damage to the endothelium (81. This may result in perivascular hemorrhages [5] and myocar- dial damage despite the rapid restoration of flow 191. It is of importance to note that in this case the patient's manifestations were only a transient phenomenon without adverse effects. The patient did not have a myocardial infarction as determined electrocardiographically or en- zymatically probably because the amount of air injected was small.

The occurrence of coronary air emboli involving the use of the microdilatation catheter can be prevented if balloon preparation is performed in accordance with the manufacturer's instructions. It is important to evaluate the dilatation catheter just before introduction into the guiding catheter particularly when the dilatation catheter is removed and exposed to air. This also may apply to any similar venting systems developed in the future.

REFERENCES

1. Bentivoglio LG, Leo LR: Death from coronary air embolism during percutaneous translurninal coronary angioplasty. Cathet Cardiovasc Diagn 11:591-595, 1985.

Coronary Air Embolism 167

5. Chase WH: Anatomical and experimental observations on air embolism. Surg Gynecol Obstet 59569-577. 1934.

6. Geoghegan T. Larn CR: The mechanism of death from intracar- diac air and its reversibility. Ann Surg 138:351-359, 1953.

7. Justice C, Leach S, Edwards S: The harmful effects and treatment of coronary air embolism during open heart surgery. Ann Thorac Surg 14:47-53, 1972.

8. Warren BA, Philp RB, Inwood MJ: The ultrastructural rnorphol- ogy of air embolism: Platelet adhesion to the interface and endo- thelial damage. Br J Exp Pathol54:163-172, 1973.

9. Amar R, Halon DA, Lewis BS; Myocardial damage following coronary air embolism during coronary angiography . Cath Car- diovasc Diagn 13:39-41, 1987.

2. Dorros G , Cowley MJ, Simpson J, Bentivoglio LG, Block PC. Bourassa M, Detre K, Gosselin AJ, Gruenztig AR, Kelsey SF, Kent KM, Mock MB, Mullin SM, Myler RK, Passamani BR, Stertzer SH, William DO: Percutaneous transluminal coronary angioplasty: Report of complications from the National Heart, Lung and Blood Institute PTCA Registry. Circulation 87:723- 730, 1985.

3. Heupler FA Jr, Ferrario CM, Averill DB, Bott-Silverman C: Initial coronary air embolism in the differential diagnosis of coro- nary artery spasm. Am J Cardiol 55:657-881, 1985.

4. Stegman T, Daniel W, Bellrnan L, Trenkler G, Oelert H, Borst HG: Experimental coronary air embolism. Assesment of time course of myocardial ischemia and the protective effect of cardio- pulmonary bypass. Thorac Cardiovasc Surg 28: 141-149, 1980.