Outcome after major dissection during coronary angioplasty using the perfusion balloon catheter

Coronary artery dissection is an infrequent but serious complication of coronary angioplasty that can lead to periprocedural vessel occlusion, emergency bypass surgery, myocardial infarction or death. Recently, a perfusion balloon catheter was developed that permits passive perfusion of blood through the central lumen of the catheter. It enables prolonged balloon inflations to be performed and has been used to provide distal blood flow after coronary occlusion. To evaluate the effectiveness of the perfusion balloon catheter in patients with major coronary dissections, 36 consecutive patients treated with the perfusion balloon catheter were compared with 46 consecutive patients treated before its availability. The 2 groups were similar in terms of clinical, angiographic and initial procedural characteristics. Use of the perfusion balloon catheter permitted a significantly longer inflation than standard balloon inflation (average 18 +/- 5 min). Angiographic success was significantly greater with the perfusion balloon catheter (84 vs 62% for conventional therapy), whereas complications were markedly reduced (48 vs 78%). With the perfusion balloon catheter there were fewer deaths (2 vs 6%), myocardial infarctions (14 vs 40%) and emergency bypass operations (11 vs 25%). The findings of this retrospective comparison demonstrate that the perfusion balloon catheter is effective for the management of major dissections after coronary angioplasty. The use of the perfusion balloon catheter should be considered when a major coronary dissection occurs and when emergency bypass surgery is contemplated.     

Assessment of left ventricular performance during percutaneous transluminal coronary angioplasty: a study by intravenous digital subtraction ventriculography

Left ventricular performance during percutaneous transluminal coronary angioplasty was assessed in 52 patients by intravenous digital subtraction ventriculography. After injection of contrast into the right atrium ventriculograms were obtained before and during balloon inflation. In 37 patients they were also obtained after the procedure. A 12 lead electrocardiogram was monitored throughout. During balloon inflation the left ventricular ejection fraction fell (from 73% to 57%) in all but one patient; the decreases in patients with single vessel or multivessel disease were similar. The fall in left ventricular ejection fraction during percutaneous transluminal coronary angioplasty of the left anterior descending artery (19%) was significantly greater than that during balloon inflation in the right coronary (10%) or circumflex (8%) coronary arteries. It also reduced anterobasal, anterior, and apical segmental shortening while right coronary percutaneous transluminal coronary angioplasty affected inferior and apical segments. In 33 (63%) patients the ST segment was altered during balloon inflation. The fall in left ventricular ejection fraction correlated significantly with the magnitude of both ST segment elevation (r = 0.637) and ST depression (r = 0.396). Left ventricular ejection fraction and regional wall motion returned to baseline values after the procedure. Balloon inflation during percutaneous transluminal coronary angioplasty produces considerable abnormalities of global and regional left ventricular performance and this indicates the presence of myocardial ischaemia, which may not be apparent on electrocardiographic monitoring. Intravenous digital subtraction ventriculography is useful for monitoring left ventricular performance during controlled episodes of coronary occlusion produced by balloon inflation.     

Assessment of left ventricular performance during percutaneous transluminal coronary angioplasty: a study by intravenous digital subtraction ventriculography.

Left ventricular performance during percutaneous transluminal coronary angioplasty was assessed in 52 patients by intravenous digital subtraction ventriculography. After injection of contrast into the right atrium ventriculograms were obtained before and during balloon inflation. In 37 patients they were also obtained after the procedure. A 12 lead electrocardiogram was monitored throughout. During balloon inflation the left ventricular ejection fraction fell (from 73% to 57%) in all but one patient; the decreases in patients with single vessel or multivessel disease were similar. The fall in left ventricular ejection fraction during percutaneous transluminal coronary angioplasty of the left anterior descending artery (19%) was significantly greater than that during balloon inflation in the right coronary (10%) or circumflex (8%) coronary arteries. It also reduced anterobasal, anterior, and apical segmental shortening while right coronary percutaneous transluminal coronary angioplasty affected inferior and apical segments. In 33 (63%) patients the ST segment was altered during balloon inflation. The fall in left ventricular ejection fraction correlated significantly with the magnitude of both ST segment elevation (r = 0.637) and ST depression (r = 0.396). Left ventricular ejection fraction and regional wall motion returned to baseline values after the procedure. Balloon inflation during percutaneous transluminal coronary angioplasty produces considerable abnormalities of global and regional left ventricular performance and this indicates the presence of myocardial ischaemia, which may not be apparent on electrocardiographic monitoring. Intravenous digital subtraction ventriculography is useful for monitoring left ventricular performance during controlled episodes of coronary occlusion produced by balloon inflation.     

Comparison of ST-segment deviation to scintigraphically quantified myocardial ischemia during acute coronary occlusion induced by percutaneous transluminal coronary angioplasty

This study compared ST-segment changes during acute coronary artery occlusion with measurements of ischemia by myocardial scintigraphy. Forty patients who were referred for elective prolonged percutaneous transluminal coronary angioplasty underwent 12-lead electrocardiographic recording before the procedure (baseline) and continuously during the entire balloon inflation (occlusion). For each patient, the summed ST-segment deviation was calculated as the maximal absolute difference, elevation or depression, between baseline and occlusion recordings in all 12 leads. Each patient underwent 2 myocardial scintigraphies, 1 with technetium-99m sestamibi injected during the balloon inflation and 1 on the following day as a control study. Ischemia that was induced by balloon occlusion was quantified in terms of extent and severity. Results for the entire study group showed that summed ST deviation correlated with extent (r = 0.59, p < 0.0001) and severity (r = 0.61, p < 0.0001) of ischemia. The location of maximal ST deviation differed for the 3 arteries. For occlusion of the left anterior descending artery, maximal ST deviation was elevated in lead V3. For occlusion of the left circumflex artery, maximal ST deviation was depressed in lead V2. Occlusion of the right coronary artery caused ST elevation in lead III and ST depression in lead V2. In conclusion, this study demonstrated a significant correlation between summed ST deviation and myocardial ischemia during coronary occlusion that is induced by percutaneous transluminal coronary angioplasty.     

Deterioration in left ventricular performance during early coronary angioplasty after thrombolysis. Evidence for myocardial salvage

To investigate the effects of controlled coronary artery reocclusion after successful thrombolysis, we studied 15 patients during early elective angioplasty of the patent infarct-related artery. Eight patients underwent left anterior descending artery dilation, and the other 7 had right coronary artery dilation. In 13 cases, ST-segment elevation developed during balloon occlusion. In all 15 cases, intravenous digital subtraction left ventriculography during balloon inflation showed that the ejection fraction decreased at least 5% (mean decrease, from 60% to 47%), despite preexisting Q waves overlying the infarct territory in 5 patients. Balloon inflation resulted in decreased apical segmental shortening in all 8 patients who underwent left anterior descending artery dilation; likewise, balloon inflation produced impairment of inferior-wall contraction in all 7 patients who had right coronary artery dilation. In this setting, a deterioration in left ventricular performance indicates that the restoration of coronary patency with thrombolysis has resulted in myocardial salvage. In patients with Q waves, such deterioration suggests that this electrocardiographic abnormality does not necessarily indicate a completed infarction.     

Left main percutaneous transluminal coronary angioplasty with the autoperfusion catheter in an animal model

Left main coronary angioplasty is associated with high risk because of interruption of blood flow to much of the left ventricle during balloon inflation. An "autoperfusion" balloon angioplasty catheter that allows blood to flow passively distal to an inflated balloon was tested in dogs and compared with inflations with standard balloon catheters. During 3 min occlusions of the left main coronary artery with the autoperfusion catheter, regional myocardial blood flow was preserved at 0.60 +/- 0.14 ml/min/g, compared with 0.07 +/- 0.03 ml/min/g during inflation with standard balloon catheters (P less than 0.01). Similarly, at the end of 3 min of inflation, left ventricular systolic pressure and dP/dt were maintained with autoperfusion catheter inflation, but they were severely depressed after standard angioplasty balloon inflation. All seven dogs survived autoperfusion balloon inflation, whereas five of seven developed sustained ventricular tachycardia and/or ventricular fibrillation during or after standard balloon inflation. Thus, distal blood flow, hemodynamics, and survival were preserved during autoperfusion balloon inflation in the left main coronary artery.     

Limitation of myocardial ischemia by collateral circulation during sudden controlled coronary artery occlusion in human subjects: a prospective study

We have shown improvement in collateral filling immediately after sudden controlled coronary occlusion in human subjects undergoing elective coronary angioplasty. It has been suggested but not proved that collateral circulation can limit myocardial ischemia. We prospectively studied 23 patients with isolated left anterior descending (n = 14) or right coronary (n = 9) disease and normal left ventriculograms during elective coronary angioplasty. A second arterial catheter was used for injection of the contralateral artery to assess collateral filling before balloon placement and during coronary occlusion by balloon inflation. Left ventriculography was performed during another inflation. Grading of collateral filling was as follows: 0 = none, 1 = filling of side branches only, 2 = partial filling of the epicardial segment, 3 = complete filling of the epicardial segment. Indexes of myocardial ischemia included percent of the left ventricular perimeter showing new hypocontractility and the sum of ST segment elevation measured on a simultaneous 12-lead electrocardiogram recorded during each inflation. Collateral filling during balloon occlusion and indexes of ischemia were assessed at 30 to 40 sec into inflation. Aortic pressure and heart rate did not correlate with the percent hypocontractile perimeter nor the sum of ST segment elevation. There was a significant correlation between the grade of collateral filling during inflation and both percent hypocontractile perimeter (r = -.85) and the sum of ST segment elevation (r = -.87). Anginal pain occurred in all patients with grade 0 or 1 collateral filling but in only 36% of patients with grade 2 or 3 collaterals. In conclusion, collateral circulation limits myocardial ischemia as assessed by the extent of new ventricular asynergy and electrocardiographic changes during coronary occlusion in patients.     

The autoperfusion balloon angioplasty catheter limits myocardial ischemia and necrosis during prolonged balloon inflation

A new balloon angioplasty catheter with multiple proximal and distal side holes has previously been shown to allow significant protection from ischemia during a 3 min balloon inflation in a coronary artery. Because of the potential benefits of very long periods of inflation, 21 anesthetized thoracotomized dogs were randomized to left circumflex coronary artery occlusion with either a standard or an autoperfusion balloon catheter for 90 min. Nine dogs sustained ventricular fibrillation before completing the study, eight after standard balloon inflation and one after autoperfusion balloon inflation (p = 0.04). ST segment elevation was 0.45 +/- 0.13 mV after 15 min of standard balloon inflation versus -0.03 +/- 0.03 mV after autoperfusion balloon inflation (p less than 0.001). Regional myocardial blood flow was 0.02 +/- 0.01 ml/min per g after 30 min of standard balloon inflation compared with 0.78 +/- 0.23 ml/min per g in the group subjected to autoperfusion balloon inflation (p = 0.01). The area of necrosis/area at risk in the standard catheter group was 40.4 +/- 19.3% versus 1.2 +/- 1.2% for the autoperfusion catheter group (p = 0.01). Thus, the autoperfusion catheter preserves blood flow and limits myocardial ischemia and necrosis despite 90 min of balloon inflation.     

Role of coronary collateral vessels during transient coronary occlusion during angioplasty assessed by hemodynamic, electrocardiographic and metabolic changes

The clinical role of collateral vessels was evaluated during transient coronary occlusion by percutaneous transluminal coronary angioplasty in 22 patients with (8) and without (14) collateral vessels. Coronary occlusion pressure, the ratio of mean coronary occlusion pressure to mean aortic pressure and myocardial perfusion pressure at 40 s of balloon inflation were significantly higher in patients with than in patients without collateral vessels. The changes in left ventricular systolic and end-diastolic pressure, maximal rate of rise of left ventricular pressure (peak dP/dt) and maximal rate of fall of left ventricular pressure (negative peak dP/dt) during balloon inflation were less in patients with than in patients without collateral vessels. Myocardial lactate was produced in patients without collateral vessels but not in those with such vessels. Marked ST segment elevation in the electrocardiogram occurred in patients without collateral vessels but either ST segment depression or mild ST segment elevation was observed in patients with collateral vessels. This study indicates that collateral vessels limit myocardial ischemia during coronary occlusion, probably as a result of increased myocardial perfusion pressure.     

Haemodynamic and antiarrhythmic protective effects of intracoronary perfusion during percutaneous transluminal coronary angioplasty

In 17 anaesthetized open-chest pigs, experiments were performed to determine if a myocardial protective effect can be obtained by intracoronary perfusion through the dilatation catheter during balloon inflation for percutaneous transluminal coronary angioplasty. Placement of the catheter such that the balloon lay in the middle third of the left anterior descending coronary artery caused a significant deterioration in haemodynamic status prior to balloon inflation, and on 5 occasions led to the development of ventricular fibrillation (VF). Balloon inflation without perfusion for periods of up to 5 min produced further haemodynamic deterioration, and culminated in VF in 4/14 cases. Simultaneous perfusion during balloon inflation (proximal perfusion pressure 900-1200 mmHg), with flow rates of 14.5 ml min-1 for arterial whole blood and 21 +/- 7 ml min-1 for blood diluted with 0.90% NaCl (haematocrit approx. 25%), not only prevented the haemodynamic deterioration but resulted in an improvement compared with values obtained with the catheter in position prior to balloon inflation. In no case did VF occur during 5 min of balloon inflation plus perfusion. The use of diluted blood as the perfusate was not associated with intracatheter thrombus formation, which was sometimes seen as a complication of whole blood perfusion.     

Left ventricular function during transient coronary occlusion: digital subtraction left ventriculograms during coronary angioplasty

The impact of transient myocardial ischemia on left ventricular function was examined by digital subtraction left ventricular angiography. Contrast medium was injected into the right pulmonary artery before, at 60 seconds of balloon inflation, and 10 minutes after balloon deflation. A total of 69 patients completed the study. In 52 patients, the left anterior descending artery (LAD) was involved, and in 17, the right coronary artery (RCA) was the focus. Ejection fraction (EF) declined by balloon inflation and returned to baseline value after deflation of the balloon. There was tendency toward a lower EF and wider akinetic area for LAD dilatation. The linear correlation between resting EF and EF during balloon inflation suggested that the effect of momentary coronary occlusion on left ventricular function appears to be additive to pre-existing left ventricular dysfunction, and resting ejection fraction is an important parameter for estimating the degree of diminished left ventricular function during myocardial ischemia.     

Ischemia during angioplasty after streptokinase: A marker of myocardial salvage

Although thrombolytic therapy can result in lysis of a coronary artery thrombus, salvage of myocardium as measured by enzymatic, electrocardiographic and regional wall motion evaluation has not been clearly documented. Many patients after successful reperfusion continue to experience recurrent chest pain. The presence of recurrent chest pain suggests salvaged myocardium. Controlled reocclusion of the infarct vessel with the use of coronary angioplasty may support evidence for myocardial salvage. Experience in 50 patients who underwent angioplasty was reviewed retrospectively. Sixteen of the 50 patients had electrocardiographic or clinical evidence of ischemia at the time of balloon inflation. Prospectively, all patients who underwent angioplasty after they had received streptokinase were evaluated, and 5 of 5 patients had chest pain and ST-segment elevation during balloon inflation. The development of ischemic changes during balloon catheter inflation suggests the presence of persistently viable, salvaged myocardium after successful thrombolysis.     

Percutaneous support devices for high risk or complicated coronary angioplasty

Indications for coronary angioplasty have expanded to include patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease and impaired left ventricular function. Several mechanical approaches have been developed as adjuncts to high risk coronary angioplasty to improve patient tolerance of coronary balloon occlusion and maintain hemodynamic stability in the event of complications. These percutaneous techniques include intraaortic balloon counterpulsation, anterograde transcatheter coronary perfusion, coronary sinus retroperfusion, cardiopulmonary bypass, Hemopump left ventricular assistance and partial left heart bypass. The intraaortic balloon pump provides hemodynamic support and ameliorates ischemia by decreasing myocardial work; it may be inserted for periprocedural complications or before angioplasty in patients with ischemia or hypotension. Anterograde distal coronary artery perfusion may be accomplished passively through an autoperfusion catheter or by active pumping of oxygenated blood or fluorocarbons through the central lumen of an angioplasty catheter. Synchronized coronary sinus retroperfusion produces pulsatile blood flow via the cardiac veins to the coronary bed distal to a stenosis. Both perfusion techniques limit development of ischemic chest pain and myocardial dysfunction in patients undergoing prolonged balloon inflations. Percutaneous cardiopulmonary bypass provides complete systemic hemodynamic support which is independent of intrinsic cardiac function or rhythm and has been employed prophylactically in very high risk patients before coronary angioplasty or emergently for abrupt closure. These and newer support devices, while associated with significant complications, may ultimately improve the safety of coronary angioplasty and allow its application to those who would otherwise not be candidates for revascularization.     

Two-dimensional echocardiography during percutaneous transluminal coronary angioplasty

In order to study myocardial and clinical events during transient coronary occlusion in humans, two-dimensional echocardiography was continuously performed in 15 patients undergoing 49 balloon inflations during percutaneous transluminal coronary angioplasty (PTCA). Transient segmental asynergy developed in all patients 8 +/- 3 seconds after balloon inflation and returned to baseline 19 +/- 8 seconds after balloon deflation. Segmental dyskinesis was seen in only 8 of 11 patients undergoing PTCA of the left anterior descending artery (LAD). A wall motion score, based on degree of asynergy of 13 segments of the left ventricle, was significantly higher during LAD than during right coronary artery inflation (7.9 +/- 1.3 vs 4.0 +/- 1.4, p less than 0.01). Left ventricular size index increased significantly during balloon inflation, from 179 +/- 9 to 196 +/- 10 mm (p less than 0.01). Four patients developed transient ST segment changes in the extremity leads of the ECG and five patients had angina pectoris. The very first sign of ischemia in three patients, who developed all of these symptoms together, was consistently asynergy, followed by ECG changes, and last, angina pectoris. Thus during PTCA, transient asynergy and left ventricular dilatation develop, which are often clinically silent.     

A novel minimal-invasive model of chronic myocardial infarction in swine

BACKGROUND: Most animal studies on myocardial infarction (MI) have used open-chest models with direct surgical coronary artery ligation, which imply local as well as generalized side effects of major surgery. Some closed-chest models of MI have been established, mainly using catheterization techniques with coronary artery embolization, balloon occlusion, and intracoronary injection of thrombogenic agents. The aim of this study was to develop a closed-chest technique of chronic coronary artery occlusion at a selected location with subsequent thrombus formation without use of balloon inflation or thrombotic chemical agents. METHODS AND RESULTS: A coronary angiography via the carotid artery was performed using a 7 F guiding catheter in 21 pigs. After insertion of a percutaneous transluminal coronary angioplasty (PTCA) guide wire into the distal coronary artery, a vessel-size adapted flexible foreign body comprising an open-cell sponge was advanced into the coronary artery via the guide wire by a non-inflated PTCA balloon. Five min after removal of the guide wire and the balloon catheter, total coronary artery occlusion was documented by angiography. Retrograde thrombosis of the coronary artery occurred in three animals. After one week, total vessel occlusion at the previously selected location was visualized by coronary angiography in animals that had survived. Macroscopic analysis demonstrated the foreign body with subsequent thrombus formation in the coronary artery and distal MI. Post-mortem histological analysis revealed myocardial necrosis and granulocyte infiltration at the margin of the infarction, without damage to remote myocardium. CONCLUSIONS: This new easy-to-perform closed-chest technique provides reproducible chronic coronary artery occlusion at a selected location with subsequent MI. It avoids major surgery and thoracotomy and does not require balloon inflation or intracoronary injection of thrombotic or chemical agents.     

Marked alternans of the elevated ST segment during occlusion of the left anterior descending coronary artery in percutaneous transluminal coronary angioplasty: clinical background and electrocardiographic features.

To investigate the clinical background and the electrocardiographic features of marked alternans of the elevated ST segment during coronary angioplasty, we examined 12-lead electrocardiograms recorded continuously during occlusion of the left anterior descending coronary artery by balloon inflation in 41 patients. The incidence of marked ST alternans was 27% of 41 patients and 15% of 117 balloon occlusions. The incidence decreased progressively from the first to the third occlusion. The time course of ST alternans was determined. Compared with patients without ST alternans, patients with ST alternans had a shorter history of angina, less severe stenosis of the target lesion before coronary angioplasty, more leads showing ST elevation during occlusion, higher ST elevation during occlusion and lower incidence of previous myocardial infarction in the left anterior descending coronary arterial area. ST alternans recorded on the surface electrocardiogram may thus be considered a marker of acute severe and extensive myocardial ischemia.     

Regional myocardial dysfunction during coronary angioplasty: evaluation by two-dimensional echocardiography and 12 lead electrocardiography

Balloon inflation performed during percutaneous transluminal coronary angioplasty causes transient total occlusion of the coronary artery and thus provides a model for evaluation of the regional myocardial responses to transient ischemia. Twenty patients with normal left ventricular function undergoing angioplasty of isolated stenosis of the proximal left anterior descending coronary artery were studied. In group A (14 patients) analysis of one inflation-deflation sequence per patient was performed. Group B (six patients) had multiple (greater than 5) inflations; the first and last sequences were analyzed. Assessment included continuous two-dimensional echocardiography with computerized quantitative analysis of regional left ventricular wall motion, and continuous 12 lead electrocardiographic recordings. The mean duration of inflation in group A was 62 +/- 6 seconds (mean +/- SD). The onset of regional left ventricular dysfunction was 12 +/- 5 seconds after inflation. Profound dysfunction was noted in all patients. After 60 seconds of balloon occlusion of the coronary artery, 29% of patients had severe hypokinesia of the ischemic region and 71% had akinesia or dyskinesia. With deflation there was prompt recovery of regional function, with full recovery at 43 +/- 17 seconds. Comparison of data from first and last inflations in group B revealed no significant differences in time to onset of dysfunction, magnitude of dysfunction or time to complete recovery of function. The onset of ischemic electrocardiographic changes lagged behind the onset of wall motion abnormalities, with only 64% of patients showing evidence of ischemia on 12 lead electrocardiograms at 20 seconds of inflation. After 60 seconds, 86% had ischemia detectable by electrocardiography. Thus, balloon inflation during coronary angioplasty leads to profound but reversible regional left ventricular dysfunction. Repeated occlusions of the coronary artery during angioplasty do not have a cumulative ischemic effect. It may be hazardous to apply these findings to patients who have underlying major left ventricular dysfunction and in whom the reversibility of dysfunction and lack of cumulative ischemic effect may not be assured.     

Preservation of regional myocardial function during coronary angioplasty with an autoperfusion balloon catheter: a case report

Echocardiographic assessment of regional myocardial function was performed during standard balloon coronary angioplasty followed by autoperfusion balloon angioplasty of a proximal left anterior descending artery stenosis. Septal and apical akinesis occurred within 60 seconds of standard balloon inflation, but regional function was well preserved during prolonged autoperfusion balloon inflation.     

Contrast perfusion echocardiography: distribution and reproducibility of myocardial contrast enhancement in coronary artery disease

A qualitative assessment was undertaken of the echocardiographic distribution of myocardial contrast enhancement after selective intracoronary injections of 2 ml of hand-agitated Urografin solution. The reproducibility and duration of contrast enhancement has also been examined. Forty-five contrast injections were given, 36 into the left and 6 into the right coronary arteries and 3 into bypass grafts of 28 patients undergoing diagnostic arteriography. Myocardial contrast enhancement occurred in 91% of cases. Although contrast enhancement appeared within the expected area of distribution of the artery infused, in no case was enhancement homogeneous. In 4 patients (1 of whom had undergone coronary bypass surgery), contrast enhancement also appeared in areas remote from the expected perfusion territory, in each case due to well established collateral supply seen angiographically. The contrast effect persisted for 71 +/- 26 seconds. Repeat injection in 5 patients (using identical echocardiographic windows) confirmed the reproducibility of the technique. No patient had symptoms related to the injections, although transient left ventricular wall motion abnormalities were observed in 3 cases. High-grade coronary stenoses did not affect distribution of myocardial contrast enhancement, although coronary occlusions produced well defined deficits. Thus, selective intracoronary injections of hand-agitated echocardiographic contrast medium produce regional myocardial enhancement, which probably reflects the perfusion territory of the artery. The technique is safe and reproducible in human subjects. Nevertheless, because regional enhancement after selective coronary injections is not homogeneous, analysis of enhancement deficits is unlikely to provide a clinically useful means of evaluating the functional significance of coronary stenoses.     

Protection against ischemia during prolonged balloon inflation by distal coronary perfusion with use of an autoperfusion catheter or Fluosol.

OBJECTIVES. The purpose of this report was to study the protective effects of passive and active distal coronary perfusion during prolonged balloon inflation. BACKGROUND. Prolonged balloon inflation has been proposed to improve immediate and long-term results of percutaneous transluminal coronary angioplasty, but it requires protection against myocardial ischemia. METHODS. A 30-min balloon occlusion of the left anterior descending artery was performed in three groups of closed chest anesthetized dogs: 1) control (no distal coronary perfusion, n = 13), 2) passive distal coronary perfusion (autoperfusion catheter, n = 10), and 3) active distal coronary perfusion (infusion of the perfluorochemical Fluosol at 30 ml/min, n = 11). RESULTS. At 10 min of balloon inflation, echocardiographic wall motion indexes (scored from 1 [normal] to 5 [dyskinesia]) in the autoperfusion catheter and Fluosol groups (2.4 +/- 1.2 and 2.0 +/- 0.9, respectively) were significantly better than in the control group (3.6 +/- 0.4, p = 0.001), but at 25 min this improvement in wall motion had attenuated and became statistically insignificant when compared with values in the control group. Left ventricular end-diastolic pressure at peak inflation in the Fluosol group (19.5 +/- 5.5 mm Hg) was higher than in the control (7.6 +/- 3.6) and autoperfusion catheter (5.3 +/- 1.4, p < or = 0.01) groups. Pathologic evidence of infarction by tetrazolium staining was seen in three control dogs and in none of the other groups (p = 0.07). Ventricular tachycardia and fibrillation were less frequent in the autoperfusion catheter group (p = 0.02). Three deaths were observed in the control dogs, two in the Fluosol group and none in the dogs with an autoperfusion catheter (p = NS). CONCLUSIONS. Passive (the autoperfusion balloon catheter) and active (Fluosol) distal coronary perfusion methods are comparable and better than no perfusion in protecting the myocardium against ischemia produced by prolonged coronary balloon inflation in an experimental canine model. This protection is transient, attenuating after 10 to 25 min, and partial because there was no significant difference in the incidence of myocardial infarction and death among groups, although the latter observations may be related to small sample size.