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.     

Preservation of distal coronary perfusion during prolonged balloon inflation with an autoperfusion angioplasty catheter

A newly designed balloon coronary angioplasty catheter that allows passive antegrade blood flow during balloon inflation (autoperfusion catheter) was compared with a standard balloon coronary angioplasty catheter. In a randomized sequence, inflations were performed for 3 min in the left circumflex coronary artery of 12 dogs with the standard catheter followed by the autoperfusion catheter or vice versa. During inflation with the standard catheter, the ST segment of standard limb lead II increased from -0.02 +/- 0.03 mV to 0.39 +/- 0.08 mV (p less than .001), whereas during inflation with the autoperfusion catheter the ST segment did not change (-0.03 +/- 0.03 vs -0.01 +/- 0.04 mV; p = NS). Regional myocardial blood flow measured by the radioactive microsphere technique in the posterior subepicardium and subendocardium was 0.12 +/- 0.03 and 0.08 +/- 0.03 ml/min/g, respectively, with the standard catheter as compared with 0.57 +/- 0.08 and 0.61 +/- 0.14 ml/min/g with the autoperfusion catheter (both p less than .01 compared with the standard catheter). Thus, unlike the standard catheter, the autoperfusion catheter allows for inflations up to 3 min in duration without producing deleterious changes in the ST segment or severe reductions in regional myocardial blood flow.     

Amelioration of ischemia during angioplasty of the left anterior descending coronary artery with an autoperfusion catheter

A new autoperfusion balloon angioplasty catheter with sideholes proximal and distal to the balloon--facilitating distal blood flow during inflation--was compared with standard angioplasty catheters in a prospective, randomized study with blinded data analysis. Hemodynamic and electrocardiographic markers of ischemia after 1 minute of standard or autoperfusion catheter inflations were compared with ischemia after control inflation with standard balloons. In the patient group randomized to standard balloon inflation only, ST-segment elevation after control inflation with a standard balloon catheter was 0.37 +/- 0.04 mV; ST-segment elevation after final balloon inflation with a standard catheter was unchanged at 0.35 +/- 0.04 mV (difference not significant). In the group randomized to the autoperfusion catheter, control inflation with a standard catheter resulted in 0.48 +/- 0.1 mV ST elevation; final inflation with the autoperfusion catheter demonstrated 0.16 +/- 0.09 mV ST elevation (p less than 0.005). Autoperfusion catheter inflation was continued for 2 minutes without change in electrocardiographic findings: ST segments remained at 0.08 +/- 0.03 mV, unchanged from 0.07 +/- 0.03 mV before angioplasty (difference not significant). Thus, while coronary angioplasty performed with standard catheters resulted in marked ST-segment elevation, in patients undergoing angioplasty with the autoperfusion catheter, ischemia was generally not seen, despite sustained balloon inflation for 2 minutes.     

Perfusion balloon catheter

An autoperfusion balloon catheter was developed to allow passive myocardial perfusion during balloon inflation, through a central lumen and multiple side holes in the shaft proximal and distal to the balloon. This report reviews preliminary experimental animal data and initial human clinical experience with this device. In our first study with this device, the duration of inflation in dogs was compared with the maximal duration of inflation using a standard angioplasty catheter. Coronary arteriography was performed to demonstrate distal coronary blood flow through the perfusion balloon catheter. Electrocardiographic recordings and repeated left ventriculograms were performed to detect evidence of ischemia during standard and perfusion and balloon catheter inflations. The average inflation time was 3 +/- 1 minute for the standard catheter and 37 +/- 10 minutes for the perfusion catheter. Each dog had evidence of severe myocardial ischemia during standard inflation, yet none of the animals had ST-segment elevation, ventricular arrhythmia or wall motion abnormality during dilatation with the perfusion catheter. In a second experiment, the effect of prolonged balloon inflations (30 minutes) on intimal hyperplasia was evaluated in the rabbit model. Results of this study showed reduction of intimal and medial hyperplasia after 4 weeks in iliac arteries in rabbits treated with prolonged inflations compared with the contralateral vessel in rabbits treated with standard angioplasty. Initial clinical results from patients treated with this new catheter are presented. The availability of an effective autoperfusion catheter should allow for testing the hypothesis that prolonged inflations could alter the acute angioplasty success rate and long-term restenosis rate.     

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.     

New concept in coronary angioplasty: Dilatation with a helical balloon that allows simultaneous autoperfusion

These preclinical studies investigate a new concept in coronary angioplasty and balloon catheter technology (the P100 catheter). The study sought to evaluate the morphology of experimental coronary arterial plaques dilated with the P100 in comparison to standard balloons, to determine the in vitro flow rates occurring during the inflation of the P100 in comparison to available perfusion catheters, and to assess the in vivo coronary flow velocity and the presence of ischemia during prolonged inflations with the P100. The development of myocardial ischemia is a major limitation of standard balloon angioplasty. To limit ischemia, autoperfusion catheters have been developed, in which blood flows through the balloon in the central catheter shaft. However, as the flow lumen profile is reduced to enhance the performance of these devices, so is the accompanying flow. An angioplasty catheter was designed to evaluate the feasibility of continuous autoperfusion around the dilatation balloon. The balloon surface was engineered to develop a helical trough for blood flow to occur during inflation. Arterial plaque morphology following angioplasty with the P100 (n = 8) and with standard balloons (n = 8) was evaluated in a swine model. In vitro flow rates during inflation of the P100 and available perfusion catheters were determined using 33% glycerol solution. In vivo coronary flow velocity was determined with a Doppler-tipped wire during 60-min continuous inflations with the P100, and 15-sec inflations with a standard balloon in 12 vessel segments in 7 dogs; using 3.0–3.5-mm-diameter balloons. All lesions were successfully dilated (<50% luminal diameter stenosis) with the P100 and standard balloons. There were no morphologic differences in plaques dilated with P100 compared to standard balloons. In vitro flow rates with conventional 3.0-mm balloon perfusion catheters ranged from 27.1 ± 2.1 ml/min (RX Flowtrack™) to 38.7 ± 0.9 ml/min (Stack Perfusion™), P < .05. Flow with the P100 ranged from 54.8 ± 4.3 ml/min (2.5-mm balloon) to 103.2 ± 4.5 ml/min (3.5-mm balloon), P <.05. Distal average peak coronary flow velocity during prolonged P100 inflations varied from 69 ± 7% of baseline at 5 min to 83 ± 8% of baseline at 40 min, with an upward trend in velocity the longer the balloon was inflated. Hemodynamics remained stable. Experimental plaques are successfully dilated with a helical balloon by a mechanism that appears similar to the dilatation mechanism of standard balloons. These preclinical studies show that angioplasty and autoperfusion can be accomplished by a balloon that does not have complete surface area contact with the vessel wall. A gap created by the helix can thus provide a conduit for blood flow. Clinical studies will determine whether this innovation, which alters the tubular geometry of current angioplasty balloons, will provide autoperfusion and equivalent dilatation effects in humans. Cathet Cardiovasc Diagn 40:109–116, 1997. © 1997 Wiley-Liss, Inc.     

New balloon catheter for prolonged percutaneous transluminal coronary angioplasty and bypass flow in occluded vessels

A new balloon catheter was developed for continuous perfusion of coronary arteries during angioplasty (CPC catheter). Steerable Grüntzig balloon catheters (3.7 mm) with two lumina were formed. The first lumen was used for balloon inflation. Side holes to the second lumen proximally and distally to the balloon were created for coronary perfusion even during inflation phase. At a perfusion pressure of 120 mmHg, a flow rate of 63 +/- 3 ml/min with 0.9% saline and 43 +/- 1 ml/min with plasma expander were measured. In experiments on five dogs, dilation time until appearance of signs of ischemia could be prolonged in three of five dogs from 30 to 40 s, 120 to 203 s, and 180 to 420 s comparing conventional and CPC balloon catheters. In 11 patients with proximal lesions, dilation time could be increased from 39.5 +/- 23.9 s to 81.1 +/- 36.3 s (p less than 0.01) until appearance of angina pectoris. ST segment changes were observed in 10/11 patients using conventional catheters. Using CPC catheters, no ST segment changes were observed in four patients; time until appearance of ST segment changes was delayed in the other seven patients. The CPC catheter seems to be an alternative catheter in proximal lesions of the left and right coronary artery, allowing the possibility of prolonged dilation and increased safety to the patient. In case of dissection or perforation, the CPC catheter can be used for perfusion of the distal part of the coronary vessel until emergency bypass surgery.     

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.     

New passive perfusion PTCA catheter

Percutaneous coronary angioplasty with a new passive perfusion balloon catheter was compared to a standard angioplasty balloon catheter during prolonged balloon inflations in miniature swine. Inflations with the passive perfusion balloon were alternated with a standard balloon with the initial balloon chosen randomly in 24 coronary arteries. End-points for terminating the balloon inflation were the appearance of 2 mm of ST segment deviation from baseline on the electrocardiogram, the occurrence of ventricular fibrillation, or 30 min of balloon inflation. During balloon inflation contrast injections were performed through the guiding catheter and flow distal to the balloon was graded 0-3 using the TIMI scale. The average (+/- SD) inflation time for the standard balloon was 3.1 +/- 2.2 minutes and for the perfusion balloon was 27.2 +/- 4.8 min (P less than 0.001). Electrocardiographic evidence of 2 mm of ST segment deviation from baseline was seen during 11/13 inflations with the standard balloon and in 3/11 balloon inflations with the perfusion balloon. Ventricular fibrillation occurred during 2/13 of the standard balloon inflations and in none during passive balloon inflations. Distal contrast flow during passive balloon inflations averaged 2.7 +/- 0.5 (TIMI scale 0-3) and was absent during inflations with the standard balloon. The perfusion balloon allowed prolonged inflations with excellent distal flow when compared to the standard balloon.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Coronary artery angioplasty with a helical autoperfusion balloon catheter

The initial in-hospital and long-term clinical experience with a helical autoperfusion balloon catheter in the treatment of coronary artery disease is reported. This new catheter design allows blood to flow passively around the inflated balloon through a protected helical channel molded into the balloon surface. Twelve consecutive patients underwent PTCA. Continuous ST monitoring, heart rate, average peak distal coronary blood flow velocity (APV), coronary blood flow (CBF), dP/dt and systemic and pulmonary arterial pressures were determined during PTCA. During balloon inflation there were no hemodynamic changes, TIMI flow was 1.7 ± 0.8, and APV was 39% of baseline. Luminal diameter stenosis improved from 61 ± 17 to 29 ± 13% (P < 0.05) following PTCA. Mean continuous inflation duration was 385 ± 215 sec and 6/12 patients had ≥ 7.5-min inflations. There were no in-hospital adverse cardiac events. One patient developed recurrent angina during 8 mo of follow-up and underwent successful PTCA of a restenotic lesion. We conclude that human plaques can be successfully dilated with a helical balloon catheter that provides autoperfusion and the ability to perform prolonged inflations with hemodynamic stability. A comparison of this PTCA catheter with standard balloon catheters is warranted. Cathet. Cardiovasc. Diagn. 40:179–185, 1997. © 1997 Wiley-Liss, Inc.     

Amelioration by nitroglycerin of left ventricular ischemia induced by percutaneous transluminal coronary angioplasty: assessment by hemodynamic variables and left ventriculography

Increasingly longer balloon inflation times during coronary angioplasty can create significant left ventricular ischemia, amelioration of which was attempted in this study using nitroglycerin. Hemodynamic variables were assessed during inflation of an angioplasty balloon in the proximal left anterior descending coronary artery of 10 patients. Regional wall motion was assessed by left ventriculography during a separate balloon inflation. Nitroglycerin (200 micrograms) was then administered intravenously, and hemodynamic and ventriculographic assessments during balloon inflations were repeated. Balloon inflation resulted in a marked increase in left ventricular end-diastolic pressure (from 9.2 +/- 2.1 to 19.4 +/- 2.9 mm Hg) and time constant of left ventricular relaxation (from 44.2 +/- 6.2 to 62.3 +/- 11.3 ms) and a decrease in distal coronary artery perfusion pressure (from 54 +/- 9 to 33.1 +/- 4 mm Hg). Time to onset of angina was 29 +/- 3 seconds and time to ST segment depression of 1 mm or greater was 30 +/- 3 seconds. Regional wall motion analysis 30 seconds after onset of balloon inflation revealed marked hypokinesia and akinesia in the anteroapical segments with graduated depression of inferior wall motion, greatest at the apex. After the administration of nitroglycerin, balloon inflation resulted in a smaller increase in end-diastolic pressure (from 5.0 +/- 2.7 to 8.3 +/- 2.6 mm Hg) and time constant (from 47.9 +/- 4.7 to 54.4 +/- 9.2 ms; both p less than 0.01 versus standard balloon inflation). Distal coronary artery pressure remained similar to standard balloon inflation (32 +/- 3 mm Hg) despite lower mean arterial pressure (89 +/- 5 mm Hg, p less than or equal to 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Hemodynamics and coronary blood flow during experimental aortic valvuloplasty: comparison of the dual versus the single catheter methods

During thoracotomy 12 anesthetized swine were instrumented and valvuloplasty catheters were positioned at the aortic anulus. Thirty-second occlusions of the left ventricular outflow tract were performed with a single catheter (n = 34) and with simultaneous inflation of dual catheters (n = 47). Left anterior descending coronary artery blood flow fell to minimums of 15% of baseline flow (SD 13.9%) during single balloon occlusion and to 63.8% of baseline flow (SD 22.8%) during dual balloon occlusion. Main pulmonary artery flow fell to minimums of 13.6% of baseline flow (SD 17.3%) during single balloon occlusion and to 66.9% of baseline flow (SD 18.3%) during dual balloon occlusion. Femoral artery systolic pressure dropped to 20.1% of baseline pressure (SD 5.6%) during single balloon occlusion and to 82.6% of baseline pressure (SD 8.1%) during dual balloon occlusion. During single balloon occlusion, 8.5 (SD 3.5) premature ventricular contractions were observed and 2.8 (SD 1.6) premature ventricular contractions occurred during dual balloon occlusion. After deflation of the valvuloplasty catheters, the time to return of baseline flow in the left anterior descending coronary artery was 28.4 second (SD 23.2 seconds) with the single balloon method and 4.8 seconds (SD 3.7 seconds) with the dual balloon method. All of these differences were statistically significant (p less than .001). During occlusion of the left ventricular outflow tract by dual valvuloplasty catheters, there were better hemodynamics, higher coronary blood flows, and fewer premature ventricular contractions than during occlusion by a single catheter. After occlusion by dual catheters, returns to baseline coronary flows were more rapid than after single catheter occlusions. These data may have application to clinical aortic valvuloplasty.     

Percutaneous transluminal coronary angioplasty utilizing prolonged balloon inflations: initial results and six-month follow-up

Coronary angioplasty (PTCA) using prolonged balloon inflation has obviated emergency coronary bypass surgery in some patients with acute occlusions at the time of PTCA. However, the use of prolonged balloon inflations has not been shown to improve long-term restenosis rates. As an alternative to the passive autoperfusion catheter, we evaluated a hemoperfusion system in which blood was obtained from the side arm of an arterial sheath and infused through the central lumen of standard balloon catheters via a modified Medrad IV pump during balloon inflation. PTCA was performed in 71 male patients (median age 57 yr). The median balloon inflation time was 4.8 minutes and the median rate of blood perfusion was 30 ml/min. PTCA was successful (lumen increase by 20 percentage points) in 83% of patients (59/71) with diameter stenosis decreasing from a median 82% to 30%. Emergency coronary bypass was required in four patients (5%). Angiographic data for six-month followup was available on 37 patients. The restenosis rate (loss of 50% of gain) was 46% (17/37). The conclusion is that prolonged balloon inflation angioplasty has a role in complicated PTCA but offers no advantage in improving long-term restenosis rates in elective PTCA.     

Use of mechanical devices for distal hemoperfusion during balloon catheter coronary angioplasty

Previous attempts to protect the dependent myocardium during balloon catheter coronary angioplasty in animals and humans have had generally unsatisfactory results. This paper summarizes the authors' experience in investigating commercially available mechanical pumps for distal coronary hemoperfusion during balloon angioplasty. Both roller and piston pumps can attain adequate distal perfusion without significant side effects in the majority of patients. Our goal was to suppress angina for at least 5 min to prolong balloon inflation in awake patients. Minor T-wave changes without concomitant angina pectoris can be expected when the distal coronary bed is perfused with hypothermic blood. Side branch occlusion by the inflated balloon prevents effective protection of the corresponding part of the dependent myocardium during distal hemoperfusion, which may result in persistent angina and ST-T changes uncorrected by increasing the hemoperfusion rate. Distal coronary diffuse spasm, rare and transient, was the only immediate complication of this procedure. It is suggested that intense local wall stimulation could occur with a higher flow rate (jet effect). Improved balloon catheter pressure/flow characteristics and on-line continuous mechanical pumps should soon make distal coronary hemoperfusion through balloon catheters an accepted clinical technique.     

Comparison of passive and active perfusion catheters: An in vitro study in a pulsatile coronary flow model

Perfusion balloon catheters are designed to provide continuous transcatheter blood flow and thereby reduce myocardial ischemia during coronary angioplasty. To compare the transcatheter flow rates of active and passive (auto-) perfusion catheters, a well-controlled experimental study was performed in a circulation model that duplicates the phasic, predominantly diastolic flow pattern of the left coronary artery. Mean diastolic coronary driving pressure varied between 20 and 100 mm Hg. For the autoperfusion catheters, a strong relationship between transcatheter flow and diastolic coronary driving pressure was found. For example, a coronary driving pressure of 80 mm Hg provided a coronary flow of 30 ml/min (RX-Perfusion [RP], ACS), 28 ml/min (Speedflow [SF], Schneider), 20 ml/min (Lifestream [LS], ACS), and 19 ml/min (Flowtrack [FT], ACS). Reduction of driving pressure to 40 mm Hg decreased the absolute transcatheter flow, which was now 16 ml/min (RP), 13 ml/min (SF), and 10 ml/min (LS and FT). The relative catheter flow (the ratio of absolute flow to baseline coronary flow rate without a catheter in place), was independent of actual coronary driving pressure and ranged between 21% ± 1% (RP) and 14% ± 1% (FT and LS). For the active perfusion system (Coreflo, Leocor, a maximal transcatheter flow of 82 ml/min was found.) Using this active perfusion system, the relative catheter flow increased with decreasing coronary driving pressure: 80→40 mm Hg: 56%→107%. For all catheters, the distal perfusion decreased between 30% (3.0 mm RP) and 50% (3.0 mm LS) by a 0.014-inch guidewire placed through the inner channel of the catheter. Because of the strong relationship between coronary driving pressure and transcatheter flow, the residual flow through all autoperfusion catheters becomes critical (<20 ml/min), when the coronary driving pressure drops below 50 mm Hg. By contrast, active perfusion systems are independent of the actual coronary driving pressure and are therefore advantageous for prolonged dilation in patients with low aortic pressure. © 1996 Wiley-Liss, Inc.     

Clinical, hemodynamic, electrocardiographic and mechanical events during nonocclusive, coronary atherectomy and comparison with balloon angioplasty.

The periprocedural events and myocardial function during nonocclusive coronary atherectomy by Rotablator or transluminal extraction catheter (TEC) may differ from events during balloon angioplasty. This may have important clinical consequences and needs to be defined further. Therefore, 17 patients undergoing Rotablator and 18 undergoing TEC atherectomy were assessed by clinical, hemodynamic and electrocardiographic monitoring and simultaneous transesophageal echocardiography. The findings were compared with similar parameters during subsequent balloon angioplasty performed in 16 of 17 patients undergoing Rotablator and 14 of 18 undergoing TEC atherectomy. Chest pain occurred more frequently during balloon inflation than during either atherectomy (p less than 0.02), whereas ST-segment and T-wave electrocardiographic changes were equally frequent. Transient second- or third-degree atrioventricular block occurred in 6 patients during Rotablator but in none during TEC atherectomy or balloon inflation (p less than 0.01 for each). Hemodynamic parameters and global left ventricular function remained unchanged during atherectomy. Regional myocardial function in the distribution of the target coronary artery, assessed by a wall motion score, was not affected during Rotablator, but deteriorated slightly during TEC atherectomy and more significantly during balloon inflation (score from 0.3 +/- 0.5 to 1.0 +/- 0.7 during TEC and 2.0 +/- 0.6 during balloon inflation, p less than 0.005 for both). Thus, chest pain is infrequent, whereas hemodynamics and global left ventricular function are preserved during Rotablator and TEC atherectomy. Transient atrioventricular block during Rotablator and regional myocardial dysfunction during TEC atherectomy may occur without significant consequences. These data suggest that these techniques may be preferable to balloon angioplasty for preserving intraprocedural left ventricular function.     

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty (PTCA)—with an autoperfusion balloon or active system—facilitates prolonged balloon inflation. Prolonged inflations may tack up intimal dissections and improve the primary angioplasty result in complex lesions. Additionally, distal perfusion may reduce the likelihood of cardiogenic shock during high-risk PTCA. Autoperfusion balloons are most frequently used to treat acute or threatened closure. There currently is no prospective clinical study showing that stent implantation for this complication is more successful and more cost-effective. The blood flow rates through autoperfusion balloons may not abolish myocardial ischemia, and higher flow rates can often be achieved with pumps. Therefore, during high-risk PTCA, pumps may be preferred to prevent hemodynamic collapse. Clinical application of perfusion pumps is hampered by the risk for mechanical hemolysis during prolonged perfusion and the high velocity of the bloodstream that exits the PTCA catheter, causing distal vessel wall trauma. © 1996 Wiley-Liss, Inc.     

Prospective analysis of possible myocardial damage or hemolysis occurring as a result of prolonged autoperfusion angioplasty in humans.

OBJECTIVES. The purpose of this study was to further explore the procedural safety of prolonged (15-min) dilation using an autoperfusion coronary angioplasty balloon by assessing the degree of myocardial damage or hemolysis, if any, occurring as a result of the procedure. BACKGROUND. Prolonged balloon inflation periods may be beneficial during percutaneous transluminal coronary angioplasty. The duration of standard balloon angioplasty is often limited by the occurrence of myocardial ischemia due to loss of anterograde blood flow. Autoperfusion angioplasty allows continued myocardial perfusion during balloon inflation and has previously been shown to reduce but not totally eliminate acute myocardial ischemia during prolonged (up to 15 min) balloon inflation. The risk of intravascular hemolysis as a result of autoperfusion angioplasty has not yet been fully delineated. METHODS. Sixty-two consecutive patients (76% men; mean age 58 years) undergoing elective percutaneous transluminal coronary angioplasty of a single lesion were studied. Serial electrocardiographic and creatine kinase MB isoenzyme data were examined to detect evidence of myocardial damage. Tests for hemolysis (plasma free hemoglobin, serum haptoglobin and serum lactate dehydrogenase) were obtained in the 1st 24 consecutive patients. RESULTS. Inflation time was 14 +/- 4 min (mean +/- SD) and the procedure was successful (less than or equal to 50% residual lesion stenosis) in 59 patients (95%). Electrocardiographic evidence of myocardial infarction (greater than 1 mm persistent ST segment depression, greater than 1 mm ST segment elevation or new Q waves) was not observed in any patient. Cardiac enzyme assays were within the normal range in all patients. No evidence of hemolysis was found in the 24 consecutive patients studied. CONCLUSIONS. We conclude that prolonged autoperfusion angioplasty can be performed in patients without clinical evidence of myocardial damage or hemolysis.